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Ari Holopainen / junkyard | |
| JUNKYARD This is location for my old lego transmissions that has been replaced by more compact and simpler designs or designs with more realistic ratios. Junkyard transmissions and reason of replacement:
JUNKYARD PART I: Main Page: A.3. Old 14-speed transmission version III, overall gear ratio 20,83: Main gearbox + range + splitter Inspirer: Scania GRS905 While gear steps and overall gear ratio are not good at version I and II, I made a new version. Now overall gear ratio is near to usual 15-20 and gear steps vary only between 1,25-1,28. Crawler gear has larger gear step on purpose so gear step CH-1L is 1,33.
I’m not sure is this correct, but I have understood that Scania’s 12-speed transmission is just 14-speed transmission without crawler gears, there are no changes in ratios or gear steps. With this manner you can also make 12-speed conversion of this lego transmission, just remove crawler gear’s 16 teeth clutch gear. New overall gear ratio is only 12,50 so 12-speed version suits to linehaul trucks. A.4. Old 14-speed transmission version IV, 6 reverse gears, overall gear ratio 40,00: Splitter + range + main gearbox, also 12- & 13-speed conversions Inspirer: Volvo I-Shift with crawler gears
I-Shift is Volvo’s 12-speed automated transmission. Now there is an option to have crawler gears in this transmission and modification is done in very interesting way: there is new high reduction gear pair between clutch and splitter unit. Normal front-mounted splitter gives 2 alternative gear pairs to get torque to main gearbox’s side axle. This new gear pair doesn’t add crawler in main gearbox but turns splitter into 3-speed version. In normal 12-speed use splitter’s crawler position is not used but when you need crawler gears this position is used with main gearbox’s gears 1st, 2nd and reverse (gives gears C1, C2 and RC). Here crawler position overrides normal splitter. Reverse crawler gear can be used also with high range so this transmission has 6 reverse gear altogether: RC, RL and RH in both ranges. Gear step RC-RL is very large and gear step RL-RH is normal splitter step which means 1 extra slow, 3 slow and 2 fast reverse gears. This description is from setup with largest number of gears, Volvo lets you choose from 4 different setups: 1 or 2 crawler gears with or without reverse crawler. Check Inspirer link for more information.
This crawler gear arrangement also means that gear step between crawler gears (C1-C2) is as large as main gearbox’s gear step 1-2. (In normal crawler gear system gear step CL-CH would be as small as other splitter steps.) Also gear step C2-1L is quite large. While normal 12 gears have already normal overall gear ratio adding 2 large gear step crawler gears give this transmission very large overall gear ratio. All in all this transmission is a little bit complex to operate but driver doesn’t need to pay attention while transmission is automated. Lego version has very good gear steps: they vary only from range shift’s 1,27 and splitter shifts’ 1,28 to compound shifts’ 1,30. As described earlier gear steps of crawler gears are larger: gear step C1-C2 is 1,67 and C2-1L 1,50. While this lego version is manual gearbox you have to be more careful with splitter unit. In conclusion: In normal use remember to use only splitter’s positions high and low. This is like operating normal 12-speed transmission with splitter and range-change unit. When low speed or high torque is needed choose splitter’s position crawler with main gearbox’s gears 1st, 2nd or reverse. Available is now more detailed shift pattern in picture Ratios or 14-speed gearbox ver4 pic1. You can also modify this lego transmission in two ways. If you replace Su(12)-M(24) gear pair with S(16)-Mu(20) in crawler gear’s gear wheels and change places of some gear pairs you get 13-speed version. In this version you choose splitter’s crawler position with main gearbox’s 1st or reverse gear for low speed driving, so altogether you have 13 forward gears and 6 reverse gears. If you remove crawler gear’s gear pairs and rearrange the rest of the auxiliary’s gear pairs you get 12-speed version which is a little bit shorter than original 14-speed. 12-speed version has overall gear ratio 16,00 and 4 reverse gears. Main gearbox stays unchanged in both versions. Check next pictures for these conversions. Now available also sequential sister transmission if you don’t have transmission driving rings. Check R.17. 14-speed truck version II in R. Sequential Transmissions. For another severe duty transmission with extra slow crawler gears I recommend to check section G. 11-speed Transmissions inspired by Eaton Fuller 9ALL. D.1. Old 9-speed transmission version I, overall gear ratio 21,60: Range + main gearbox Inspirer: Eaton Fuller convertible 9 to 13
This 9-speed transmission is a little brother of the earlier 13-speed transmission, Version II. Now auxiliary gearbox has only range-change unit, so its length is very short. Also the whole transmission is a quite compact construction.
This transmission is very easy to convert into 13-speed transmission. This auxiliary gearbox already has gear ratios low range and high range, splitter low (means gears C-1-2-4-5L-6L-7L-8L in 13-speed transmission). All you need is to add gear wheels of the high range, splitter high and more longitudinal space for the sliding axle construction to get gears 5H, 6H, 7H and 8H. Check previous 13-speed version III to see how to do conversion. E. Old 18-speed Transmission, 4 reverse gears, overall gear ratio 24,00: Range + main gearbox + splitter Inspirer: Eaton Fuller 18-speed transmission
This transmission is almost like Eaton Fuller 18-speed gearbox. It has 18 forward gears and 4 reverse gears. In real Fuller transmission range-change unit and splitter unit are in the same auxiliary gearbox, but this lego version has separate range and splitter unit. Forward gears are: CL-CH-1L-1H-2L-2H-3L-3H-4L-4H-5L-5H-6L-6H-7L-7H-8L-8H.
This gearbox is pretty long. If you have problems with longitudinal space, you can build this gearbox without splitter unit. In that case you will get synchromesh 9-speed gearbox.
G.2. Old 11-speed transmission version II, overall gear ratio 37,50: This version II has 3 modifications compared to version I: range-change unit is now sliding axle solution with slightly slower deep reduction range, main gearbox is changed from underdrive to direct drive and reverse gears are a little bit faster.
I.1. Old 10-speed transmission version I, overall gear ratio 18,00: Range + main gearbox Inspirer: Eaton Fuller FR-10C In this first version solution for gearbox matching is that gear steps are mainly 1,39-1,43 but gear steps 3-4 and 8-9 are only 1,26, which means 2 exceptions in geometrical gear steps. In reality smallest step should be 4-5 and 9-10. There is also another annoying thing: reverse gears are too slow. Overall gear ratio is near to inspirer’s ratio series C.
I.2. Old 10-speed transmission version II, overall gear ratio 15,00: Main gearbox + range Inspirer: Eaton Fuller FR-10B I wasn’t happy about the (now replaced) version I so I designed version II (version IV of all 10-speeders). This time gear steps are mainly 1,33, range shift is 1,35 but gear steps 3-4 and 8-9 are 1,41. Gear steps are still not good but they are much better than in replaced first version. Another improvement is that reverse gears have now better ratios. This time overall gear ratio is near to inspirer’s ratio series B. Unlike many other transmissions in these pages this is an overdrive gearbox.
J. Old 12-speed Twin Splitter Transmission, 3 reverse gears, overall gear ratio 12,50: Main gearbox + splitter Inspirer: Eaton Twin Splitter
This transmission has 4-speed main gearbox and 3-speed splitter unit. There are also 3 reverse gears. There is available also alternative setup in which main gearbox and splitter are located parallel. To get more compact and simpler design reverse gears have different ratios and new location in shift pattern compared to original design. Also splitter’s gear order is changed to low-high-medium while in original design it’s high-medium-low (from front to rear). For usable shift levers of splitter check building examples. The idea in real twin splitter transmission is that you don’t have to shift main gearbox often, most of the shifts are easy splitter shifts. Top three gears cover quite large speed area, so you need only splitter shifts from higher city speed limits to highway speeds. On the other hand, skipping gears is more difficult than in transmission with 2-speed splitter. If you shift only with main gearbox (e.g. from 1st to 4th gear) there is a huge gear step, which is usable only in low gears with unloaded truck or in downshifting. In other situations you have to shift with splitter even if you skip gears. One possible upshifting combination is 3-5-7-9-10-11-12. 3-5 and 5-7 are combined main gearbox and splitter shifts, 7-9 is a splitter shift, 9-10 is a combined shift and the rest are splitter shifts. I’m not sure why it’s called twin splitter, but here is my guess. You have 2 splitter units, the first one has an underdrive gear and a direct gear and the second has a direct gear and an overdrive gear. When you put these 2 together, you don’t need 2 direct gears. Altogether you’ve got 2 splitters and 3 speeds => twin splitter. O.3. Old 6-speed transmission version II, light truck, overall gear ratio 8,93: Inspirer: ZF S6-66 Here is 6-speed version. It’s more complicated than 5-speed version while you need so many different gear steps after synchro parts.
There is an additional splitter unit which enlarges ZF’s transmission S6-66 to 12-speed version. Check O.8. 6-speed & 12-speed for more information. O.4. Old 6-speed transmission version IV, light truck, overall gear ratio 8,16: Inspirer: ZF S6-66 Here is another 6-speed light truck transmission. Structure before synchro axles is simpler than in previous 6-speed version but after synchro axles structure is more complicated. All in all this transmission is quite small for 6 speeder that has progressive gear steps.
One notable thing in this transmission is XS(8)-M(24) gear pair after synchro parts. So there are significant overdrive situations in some gear wheels in some gears which can lead to bad efficiency. So it’s worth to test this transmission before using it in lego vehicle. While input axle is supported by two technic brick 1x2 with 2 holes you may have difficulties to attach studded lego motor to the input axle. If you need hints to solve this problem check 4-speed version II in personal car transmissions. P.16. Old 4x2-speed personal car transmission, overall gear ratio 4,59: Inspirer: Mitsubishi Cordia Super Shift Mitsubishi used this kind of transmission in late 70’s and 80’s. It’s based on normal 4-speed gearbox with progressive gear steps but contains also 2-speed auxiliary, which is splitter-type. Auxiliary’s shift lever has positions Power (low) and Economy (high). Altogether you have 8 gears but it’s difficult to use them all in upshifting procedure while every other shift would be 2 stick shift. Typical use is to accelerate with Power mode and drive with Economy mode so you have 5 progressive gears. Auxiliary is handy in speed where upper gear has too low engine rpm but lower gear too high rpm while you can choose gear between them. If you drive in Economy mode and need to slow down a little or accelerate fast you can quickly downshift to Power mode and after situation upshift to Economy mode. While auxiliary shift is only forward/rearward movement there is no risk to shift to wrong gear.
P.17. Old 3-speed & transfer case version III, overall gear ratio 3,00: Transfer case’s gear step 2,40 Inspirer: Willys Jeep This transmission is based on old legendary off-road vehicle, Willys Jeep. It contains 3-speed main gearbox with reverse gear and 2-speed transfer case, which is part time 4WD. On the road vehicle is rear wheel drive but for difficult conditions you switch on front axle’s drive. While there is no centre differential in this transmission it’s not recommended to use 4WD in good driving conditions. Transfer case has 2 shift levers: one is for low and high selection and other switches front wheel drive on and off.
Note that front and rear output axles are coaxial but they are not directly connected together. (Front output axle is grey and rear output axle black.) To enable switching front axle’s drive on and off connection is done by four 12 teeth gears and side axle. While 12 teeth gears are double bevel type switching front wheel drive on should be easier than in versions based on 8 or 16 teeth gears. Also main gearboxes of B. 12-speed transmission can be used as 3+R-speed personal car transmissions. On the other hand this main gearbox can be used in that 12-speed transmission as alternative main gearbox. Alternative setup for this transfer case version III and other transfer cases are now located in chapter C. Transfer Cases on page Basic & special designs Q.1. Old 4-speed double clutch gearbox, overall gear ratio 4,50:
This 4-speed double clutch gearbox has pretty large gear steps so it’s wide ratio version.
While this lego version is not automatic you have to shift gears manually. Here is how it works: First you shift 1st gear with shift lever 1-3 and then move off with engaging drive line 1 in double clutch unit which is in input axle. While driving with 1st gear you preselect 2nd gear with shift lever 2-4. When it’s time to shift you only shift double clutch unit. Now in 2nd gear drive line 2 is active but 1st gear is still engaged. It’s time to disengage it and preselect 3rd gear. And again shifting happens with double clutch unit. 4th gear is shifted with same manner. And why it’s designed so that synchro parts are on the output axle? Gearbox is so long and there are difficulties to arrange shift levers. Well, reason for that is in 1st and 2nd gear. If synchro parts are located right next to double clutch there will be large ratio after them in 1st and 2nd gear. So when driving in high gears 16 teeth clutch gears of 1st or 2nd gear will spin very fast which means bad efficiency in lego world. That’s why it’s better to locate synchro parts at the end of the drive lines. Lego version is not so handy as real double clutch gearbox but it’s remote control friendlier than truck or tractor gearboxes I have designed. With 3 small motors it’s possible to build remote control shifting system. Shifting mechanisms don’t have to stop in neutral while gears are preselected. Only time you need a neutral in double clutch unit is if you want to stop without stopping driving motor. Q.2. Old 4-speed double clutch gearbox version II, overall gear ratio 3,33: Operational principle of this version II is same as in previous double clutch gearbox so if you need information how it works check previous chapter. In this version gear steps and overall gear ratio are smaller so this is close ratio version.
Porsche has had 4-speed double clutch gearboxes in the 80’s but I didn’t find ratios of those gearboxes. My guess is that ratios of this lego version are closer to ratios that Porsche used, while sport cars often use close ratio gearboxes. R.1. Old 4-speed sequential gearbox, overall gear ratio 4,00: It’s also possible to build a 4-speed sequential gearbox with progressive gear step, but it wasn’t easy to find proper gear wheels and ratios. There are a suitable gear pairs for the fifth gear but it’s not very practical to build 5-speed sequential because it will be too long construction.
R.2. Old 4-speed sequential gearbox version II, overall gear ratio 4,29: Here is another version of 4-speed sequential transmission. This time it’s overdrive version. Overdrive gear is more complicated than other gears because proper ratio needed thin 14 teeth bevel gears which can’t be used with sliding axle. That’s why there is a side axle. This version II is one stud shorter than previous sequential gearbox. Overall gear ratio is quite large for a 4-speed gearbox so this one is wide ratio version.
JUNKYARD PART II: Main Page Continues: S.1. Old 8+4R-speed tractor transmission, overall gear ratio 11,90: Main gearbox + 2+R-speed auxiliary Inspirer: Ford 6610 Dual-range
I met this kind of transmission in my teenage years when I drove shortly one Ford tractor (I don’t remember model number any more). This tractor was rear wheel drive and its top speed was 30 km/h. It has 4-speed main gearbox without a reverse gear. Auxiliary gearbox has 2 forward gears and a reverse gear. So altogether you’ve got 4 slow gears and 4 fast gears in forward plus 4 slow gears in reverse. This kind of transmission is ideal when you have to drive slow and change often driving direction. The idea is to choose suitable gear in main gearbox and then use only auxiliary. On the other hand this kind of transmission isn’t good at high speed driving although you can move off as high gear as 7th if you are unloaded and slide the clutch a little. When you drive with 8th gear and need to reverse you simply choose gear R4 with auxiliary shift lever. But to drive forward fast again you have to shift with the both sticks to get 5th, 6th or 7th gear, which are suitable gears to move off. If you need shorter lego transmission you can also locate main gearbox and auxiliary parallel. Check pictures and video of alternative setup. This modification makes auxiliary’s high range a little bit more complicated but it doesn’t change ratios or gear steps. If you build this you have to be careful with two shift levers while they are also parallel. There is a gap between main gearbox and auxiliary so you can put longitudinal brick with holes there. Then put shift lever axles only half studs inside this middle brick so shift lever axles are independent and supported at the both ends. S.2. Old 16+8R-speed tractor transmission, overall gear ratio 13,61: Splitter + main gearbox + fwd/rev+range Inspirer: Ford 6610 Dual Power
This 16+8R-speed tractor transmission is big brother of the previous 8+4R-speed transmission. Like earlier it has 4-speed main gearbox and 3-speed auxiliary, which has Lo and Hi range in forward plus (low) reverse (named as fwd/rev+range). But now real transmission has also Hi-Lo powershift. In lego version powershift is replaced with splitter because powershift is not possible with legos. Splitter has shift lever auto locking to make it easier to use. Adjust tightness of rubber belt with bricks so that locking pin doesn’t move while driving but jumps up easily when shift lever is moved. There is available also alternative setup in which main gearbox and fwd/rev+range-auxiliary are located parallel to get shorter transmission. Splitter is also modified so that it has different gear wheels but ratios and gear steps are same as in original setup. Building tip: for shift lever axles put longitudinal brick with holes also between main gearbox and fwd/rev+range and then both shift lever axles only half studs inside it. One notable thing in this lego and Ford’s transmissions is that low and high range overlap each other a little so that 4H is faster than 5L. But this doesn’t affect to your driving because shift 4H-5L would need shifting in all 3 gearboxes at the same time and normally you don’t even change range while moving. Lego remote shift splitter (crash box) While lego version’s splitter is sliding axle type you can attach gear rack to its shifting system and use small motor to slide the shifting axle. In this example is used micro motor on electric plate. So this way you get remotely shifted crash box splitter which is a little bit closer to real powershift than manual splitter. While it’s not powershift and uses sliding axle technic I can’t guarantee that it can complete the shift in every driving situations. Note that pictures show only principle how you can do remote shift, motor will need more support if you really build this.
This structure can be adopted also to 24+8R-speed tractor transmission that has 2-speed splitter representing powershift. But this shifting system doesn’t work very good in 3-speed splitter of 45+45R-speed tractor transmission because it’s difficult to stop sliding axle into middle gear while there are no steps in shifting system. So in that case it will be better to replace splitter with 3-speed powershift that uses two motors and a planetary gear. S.3. Old 12+8R-speed tractor transmission, overall gear ratio 40,82: 4-speed main gearbox + 2+R-speed auxiliary + on/off creeper unit Inspirer: Valmet 900 (TractorData)
This 12+8R-speed tractor transmission is based on 8+4R-speed transmission, which has 4-speed main gearbox and 2+R-speed auxiliary (fwd/rev+range) which means low and high range in forward plus (low) reverse. Now there is also a creeper unit which gives 4 more gears in both driving directions. When extra low speeds are needed creeper range can be switched on together with low and reverse range in normal auxiliary. There is available also alternative setup in which main gearbox and 2+R-speed auxiliary are located parallel to get shorter transmission. Also creeper unit is moved from rear to front. Building tip: to support both shift lever axles put longitudinal brick with holes also between main gearbox and 2+R-speed auxiliary and then both shift lever axles only half studs inside it. There is also a cousin 12+8R-speed transmission in E. Flat Gearbox Designs, page Basic & special designs. Some Valmets have 8+4R-speed basic transmission like some Ford Tractors. Valmet has two alternative optional equipment: either creeper unit or mechanical splitter, but not both. With creeper unit transmission is 12+8R-speed and enables extra low speed driving. Splitter unit doubles the number of gears and halves the gear steps so transmission is 16+8R-speed and it’s for more accurate working speed control. I haven’t modeled splitter version but you can copy splitter (gear step 1,20) from later shown 24+8R-speed tractor transmission and use it instead of creeper unit to get 16+8R-speed version. S.6. Old 12+12R-speed tractor transmission, overall gear ratio 15,63: 6-speed main gearbox + 2+2R-speed auxiliary Inspirer: Massey Ferguson 4608
This tractor transmission has 6-speed main gearbox (without a reverse gear) and auxiliary with four positions: slow and fast in both driving directions. Altogether you’ve got 12 forward gears and 12 reverse gears, which means that you can drive rearward as fast as forward if you have the guts. Actually this is unnecessary in lego transmissions because lego motor works in both directions and you don’t need reverse gears.
Massey Ferguson’s transmission has one difference compared to this lego transmission. Massey Ferguson’s transmission has three sticks: one is for main gearbox, other for range unit and third for driving direction changer. Lego transmission has only two sticks because range unit and driving direction changer are combined in one auxiliary. Massey Ferguson’s driving direction changer is a power shuttle, which means that while moving you can change driving direction simply moving changer’s shift lever, no clutch pedal is needed during operation. But I don’t know how high gear or speed you can change direction. In lego transmission you change driving direction with auxiliary shift or by changing motor’s rotation direction. Also Valtra has 12+12R-speed transmission that has 6 main gears with 2 ranges. S.8. Old 16+16R-speed tractor transmission, overall gear ratio 18,67: 4-speed main gearbox + fwd/rev + 4-speed range Inspirer: John Deere 6430 PowrReverser (TractorData)
This tractor transmission has 4-speed main gearbox, driving direction changer and 4-speed range unit (ranges A, B, C and D). Altogether you have 16 gears in both driving directions.
Ranges overlap each other so that top gear of lower range is faster than 1st gear in higher range. Idea is that you choose suitable range before you move off and then use only main gearbox and driving direction changer. If you need to move off in lower range than you are about to drive, it’s possible to change range without shifting also main gearbox while range’s gear steps are relatively small. This way you can avoid difficult two stick shift. For example in heavy loaded transport situation John Deere recommends upshifting sequence (A1)-(B1)-C1-D1-D2-D3-D4. Note that in John Deere’s range unit gear step B-C is smaller than others. Reason for this is to get more suitable gears for field working speeds for farm tractors. I haven’t copied this feature to this lego transmission in which all range steps are 2,00. But there are available two versions in which range step B-C is smaller than others: next 16+16R-speed version II and sequential version 16+16R-speed tractor in R. Sequential Transmissions. So check them to see how good variety of ratios with small steps is available and how difficult it can be to choose right gear when you drive like a pro. Although this transmission and 12+12R-speed transmission version II are inspired by different tractors, main gearbox’s ratios of 12-speed transmission fitted perfectly to this 16-speed transmission. So this transmission’s main gearbox and driving direction changer are taken directly from 12-speed transmission, the only new part is 4-speed range unit. It reduced a lot LDraw file design time. On the other hand main gearbox is again overdrive version which is not practical in tractor use. Note that range unit’s input axle has independent coaxial “friend axle” next to it: dark grey 8 teeth gears are on the input axle and light grey 8 teeth gear is on the friend axle. So don’t attach these axles together if you build this transmission. This arrangement is to get only 2 stages in ranges B-D have while range A has 4 stages with extra side axle. Otherwise you have to make 3-stage construction to get slowest ratio which means little poorer efficiency in higher ranges. S.9. Old 16+16R-speed tractor transmission version II, overall gear ratio 13,78: Fwd/rev + 4-speed range + 4-speed main gearbox Inspirer: John Deere 6430 PowrReverser (TractorData)
Also this 16+16R-speed tractor transmission has 4-speed main gearbox, 4-speed range unit (ranges A-D) and driving direction changer. Unlike previous version I this transmission has synchro range unit, sliding axle driving direction changer and direct drive main gearbox. Main gearbox and range unit are located parallel which makes structure short but wide. So this one is more like next 12+4R-speed alternative setup and its upgraded version 21+7R-speed. For shift lever axles put longitudinal brick with holes also between main gearbox and range unit and axles only half studs inside middle brick.
Like in previous 16+16R-speed ranges overlap each other, and now range step B-C is smaller than others. Idea is copied from John Deere’s transmission and is to get more gears for field working speeds (4-12 km/h). When you sort gear ratios you can see that there are good small gear steps in middle gears so you can get right speed for every working situation. But choosing right gear is not so easy while most of the sequential gears are in different ranges, check table Ratios sorted in picture Ratios. These small steps are for working speed control and you are not supposed to use all these gears in upshifting procedure, two stick shifts are just too complex. John Deere’s recommended upshifting sequence from stop to full speed is (A1)-(B1)-C1-D1-D2-D3-D4. Because range steps are larger than steps of main gearbox you upshift between ranges first. But you can always keep things simple so that you choose first suitable speed range with range unit and then use only main gearbox and driving direction changer. Changing between forward and reverse is this lego version’s weak point while driving direction changer is sliding axle version. Especially this original setup is problematic due to used XS(8) and S(16) spur gears. When main gearbox and range unit are synchro versions 3rd synchro gearbox would be too much because of the backlash problems. So I guess that those who will build this transmission will use motor to change driving direction. S.11. Old 24+8R-speed tractor transmission, overall gear ratio 12,60: Splitter + 4-speed range + 3-speed main gearbox Inspirer: John Deere 9430 PowrSync
This 24+8R-speed transmission is enlarged version of previous 12+4R-speed transmission. 3-speed main gearbox with a reverse gear and 4-speed range unit (ranges A-D) are taken directly from 12+4R-speed alternative setup. New feature is 2-speed splitter so you got 24 forward and 8 reverse gears altogether. In John Deere’s transmission is of course Hi-Lo powershift but other difference is that D range is not available in reverse so it has only 6 reverse gears. If you need more information about powershift check earlier 16+8R-speed tractor transmission.
In lego version main gearbox and range unit are located parallel to get shorter transmission. For shift lever axles put longitudinal brick with holes between gearboxes and then axles only half studs inside it. If width becomes a problem you can also put main gearbox and range unit sequential like in 12+4R-speed original setup but then transmission will become quite long. In pictures splitter is equipped with simple shift lever locking. If you need shift lever auto locking done by locking pin and rubber belt check YouTube video Building example. There is also one unwanted feature in lego version: gears B3-H and C2-L has same ratio 3,00. While gears have different ranges and different splitter positions we can accept that, can’t we? :-) And as an extra feature also this lego transmission can be equipped with remote shift splitter (crash box). You need micromotor, electric plate, gear rack and some other parts to get motorized sliding axle shifting for splitter. Check next pictures to see how to do it. You also need some fine tuning before use: move 12 teeth gear of the sliding axle a little bit forward so that it won’t mesh other gear wheels with its whole width. This way you can be sure that there is a neutral position between splitter’s low and high gear. Otherwise low and high gear will be connected at the same time during shifting which will temporarely lock the whole transmission and stop your tractor. And while this is crash box, not powershift, I don’t guarantee that it can complete the shifts in every driving situations.
Alternately you can replace splitter with C.7. 3-speed powershift for tractor version II and use it as 2-speed version. It’s made from two motors and a planetary gear and gives same gear step 1,20. More info about this powershift option is in page Planetary gears. T.6. Old 30+15R-speed tractor transmission, overall gear ratio 126,00: 5-speed main gearbox + 3-speed range + 2+R-speed fwd/rev+split Inspirer: Deutz-Fahr Agroplus
This tractor transmission has 5-speed main gearbox, 3-speed range unit and 2+R-speed forward/reverse+split type auxiliary. So in this transmission reverse gear is combined with splitter, not with range unit like in earlier introduced 2+R-speed auxiliaries. Altogether you have 30 forward and 15 reverse gears in this transmission so in forward number of gears is doubled and gear steps are halved compared to reverse.
Idea in this transmission is that you can split forward gears to get more accurate working speed control but in upshifting procedure splitting is not useful while you will need also difficult two stick shifts. So in upshifting you start with low split, shift first only main gearbox and as last upshift shift to high split. In reverse you have only main gear steps but 15 reverse gears cover the whole speed range so you have also fast reverse gears. Range unit have not only low and high range but also creeper range and ranges don’t overlap which makes overall gear ratio very large and allows very low speed driving. This transmission gives 45 different gears but you can still have more gears so check big brothers of this transmission, next 45+45R-speed tractor transmissions. T.10. Old 20+20R-speed tractor transmission, overall gear ratio 17,04: 5-speed powershift + 4-speed range Inspirer: Valtra N104 HiTech Check “N Series” and “N104 HiTech” on My Valtra Machine
This lego 20+20R-speed tractor transmission has 5-speed powershift and 4-speed range unit (ranges A, B, C and D). Range unit has same ratios as in 16+16R-speed tractor transmission. 5-speed powershift contains 3 motors and 2 planetary gear version III:s and is introduced in C.8. 5-speed powershift for tractor in page Planetary gears. So visit there to understand how this powershift works. You need a battery box and two forward-stop-reverse switches to operate this system. Picture called Wiring shows how you have to connect motors, switches and battery box.
Idea in this lego transmission is that you first choose suitable speed range with range unit. After move off you can enjoy powershiftable, remote controlled shifting with no need to stop for shifting and no H shift patterned shift lever. All you need is to choose driving direction with battery box’s switches and adjust speed with 2 switches. Idea for this transmission is taken from Valtra’s HiTech transmission which has 5-speed powershift, 4-speed range unit (optional equipment 2 creeper ranges) and powershuttle. It has no normal main gearbox or no shift lever with H shift pattern, all shifts are done by up & down buttons or automatic. When you change range while driving powershift shifts automatically most suitable powershift gear. You can choose automatic shifting even so that there is automatic shifting between ranges C and D, not only in powershift gears. There is also a driving mode in which you can adjust engine rpm:s where up- and downshiftings happen. I found these features in Valtra’s manuals but these are not all incredible features in Valtra tractors. All in all you can say today’s tractor transmissions are very hitech systems, not only just Valtra’s transmissions. Basic & Special Designs: C.4. Old 3-speed semiauto & transfer case ver IV Inspirer: Ford Bronco II This original 3-speed semiautomatic & transfer case version IV is based on off-road vehicle that has 3-speed automatic gearbox with torque converter and 2-speed part time 4x4 transfer case. In lego version 3-speed semiautomatic “main gearbox” is actually 2 motors and a planetary gear. For more information you can check B.8. 3-speed semiautomatic in Planetary gears.
This lego design shows only principle for these gearboxes, structure is not optimized and is quite space consuming. So it’s better to use alternative setup of this transfer case or to make request for more compact design. :-) Planetary Gears: C.8. Old 5-speed powershift for tractor 3 motors & 2 planetary gear ver III:s
This 5-speed powershift contains 3 motors and 2 planetary gears. Both planetary gears are version III with basic ratio 6,00. Motor 1 is connected to sun gear A1 and motor 2 to sun gear B1. Planet carrier 1 is connected to sun gear B2. Motor 3 is connected to sun gear A2 while planet carrier 2 works as output. This powershift is designed for 20+20R-speed tractor transmission that has 5-speed powershift and 4-speed range unit and is inspired by Valtra HiTech 5 transmission.
You need one battery box and two forward-stop-reverse switches to operate this system. Switch 1 controls rotating of motor 1 and switch 2 controls motor 3. Motor 2 orders driving direction and is wired direct to battery box, check picture called Wiring. Note that position reverse in switches 1 & 2 means that their motors run in different direction than motor 2. So switches in reverse with battery box in reverse means that motors 1 & 3 rotate actually in forward. Here is how you get the gears: To get 1st gear put both switches 1 & 2 in reverse, then move off with battery box’s switch forward or reverse. Shift to 2nd gear is that you stop motor 1 with switch 1. For 3rd gear you turn switch 1 into position forward. Now it’s time to use switch 2 to stop motor 3 and you get 4th gear. 5th gear is shifted by turning switch 2 into forward, so all motors turn in same direction and you have direct gear. Downshifting is this operation reversed so first you use switch 2 to get 4th and 3rd gear and then switch 1 to get 2nd and 1st gear. If you get confused and use switches in wrong order that’s not a problem. Only thing that happens is slightly different ratios in middle gears. For example switch combination reverse & stop still gives 2nd gear, reverse & forward 3rd gear and so on. So all in all this motor-gearbox unit gives 5 powershiftable gears with remote control shifting, no stopping for shifting, no shift lever with H shift pattern. Note that this version shows only principle how to build 5-speed powershift. To get it more compact and more usable to lego tractor you can try this: Locate motor 2 above motor 1 (remember to move also idler gear). Then move motor 3 to motor 2’s old place and change longer input axle. Move planetary gear 2 six or seven studs forward. This way you get shorter powershift. If height is not a problem you can do also this: locate motor 3 under motor 1 and move planetary gear 2 coaxial with it. Now you get also narrower version. Building tip: move planet carriers a little bit rearward on their axle to prevent possible collision problems between idlers and planet wheels. C.9. Old 9+9R-speed full powershift tractor transmission 3 motors & 2 planetary gear ver III:s
This transmission has incredible 9 remotely shiftable powershift gears in both driving directions. It contains 3 motors and 2 planetary gear ver III:s. First planetary gear has basic ratio 2,67 and second 1,67. Motor 1 is connected to sun gear A1 and motor 2 has ratio 0,67 before it’s connected to sun gear B1. Planet carrier 1 is together with sun gear A2. Motor 3 is connected to sun gear B2 and planet carrier 2 is output.
To operate this system you need one battery box and two forward-stop-reverse switches. Switch 1 is between motor 1 and battery box, switch 2 between motor 2 and battery box while motor 3 is connected directly to battery box. So, motors 1 & 2 are for speed control and motor 3 orders driving direction. Here is how you get the gears: In 1st gear both switches are in reverse. Shifts to 2nd and 3rd gear are done by moving switch 1 into stop and forward. Shift 3-4 is more difficult while you shift switch 1 back to reverse and switch 2 to stop at the same time. Shifts to 5th and 6th gear are again done by moving switch 1 into stop and forward. In shift 6-7 you move switch 1 into reverse and switch 2 into forward. Shifts to 8th and 9th gear are done with switch 1. How to connect motors, switches and battery box and how to select gears are described also in picture Wiring. 9 gears in both driving directions and overall gear ratio 10,00 are ok for a tractor transmission but gear steps are bad in this lego transmission. Steps 7-8 and 8-9 are far too small and step 1-2 is too large. It was very difficult to get usable ratios and gear steps and for a long time it looked like 9-speed powershift with proper gear steps and overall gear ratio is not possible at all. Tractor transmissions need geometrical gear steps while high gears are only for transportation and main work is done in middle gears. In some tractor transmissions steps in middle gears are even smaller than steps in high and low gears. Using tip: If you find compound shifts too difficult you can skip some gears. First upshift through gears 1-3 with switch 1 and then from 3rd to 6th and further from 6th to 9th with switch 2. This way you get 5 powershift gears and easy operating. Gear step 3-6 would be too large for real tractors but it doesn’t matter in lego use. Building tip: Use bushes in output axle to move planet carrier 2 a little bit to forward. It will move also part planet carrier 1 & sun gear A2 to forward but that is possible because 8 teeth sun gear A1 goes a little bit inside planet carrier 1. This fine tuning is to prevent possible collision problems between planet wheels and idlers. There is one possible problem in this transmission which I can’t test while I don’t have three identical motors: rotated motor starts to rotate stopped motor under high driving resistance. Motors are connected to planetary gears in such way that motor 3 shouldn’t be able to rotate motor 1 or 2 or motor 2 shouldn’t rotate motor 1. Most problematic is that if motor 1 starts to rotate motor 2. This means gears 4 and 6 when motor 1 is used and motor 2 stopped. If problem occurs you can put 24 teeth clutch gear together with axle pin with friction to mesh motor 2’s 24 teeth gear. This helps motor 2 to be stopped but it also reduces efficiency when motor 2 is used. So, if anyone builds this 9-speed powershift let me know how good it works. :-)
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