[MOC] New Compact Transfer case (Diff lock, 2WD, 4WD Hi, 4WD Lo, AWD)

[damian_kane_iv]

I've been working on my FJ Cruiser chassis and spent some time improving the gearbox, transfer case and drive line. 

I think Ive finally cracked my transfer case problem with a design that includes a center differential, 4WD Hi, 4WD LO, 2WD, and a differential lock. It can be operated manually using 2 switches. While the FJ Cruiser does not have a central diff (unless it has a manual transmission), I wanted to add a central differential because I've heard it's beneficial to RC MOCS and it could be generalized to other 4WD models. I think this T-case is possible without the center diff, but it would need some tweaking for sure..

I also made some effort to make the shifting pattern resemble real FJ controls (I used my personal FJ Cruiser as a reference :) ). 

This is the top. Transfer case is in the yellow 11 x 7 frame and the 1st row of gears after the green flip-flop. 4-speed transmission is inbetween the black and grey 5 x 7 frames:

 

Here is the underside. T-case includes the two gears touching the white 11 x 7:

 

Here are the shifting positions:

Neutral:

 

2WD:

 

4WD Hi:

 

4WD Lo:

 

Diff locked 4WD Lo:

 

 

 

[lmdesigner42]

That's a pretty compact mechanism, looks well-braced too. Does the transfer case spin okay in the Diff locked 4WD Lo position? It looks to me like in this position the rear output has a 1:1 ratio (same as 2WD), while the differential casing has a 3:1 ratio. I think that when the the differential is properly locked the casing and output should spin at the same speed.

[damian_kane_iv]

I'll have to double check. To be honest, I didnt intend to create a diff lock; that switch was meant only for 2WD, but I discovered it by accident while testing it out.

I tried some spinning in 4Lo with the lock and I didnt remember any issues, but I'll have to double check after work.

[SNIPE]

Great work, can't wait to use this in my ultimate 42177 MOD, but I will make it be 4 speed+DNR+HI/LO with the diff lock being a fully independent function

[damian_kane_iv]

16 hours ago, lmdesigner42 said:

That's a pretty compact mechanism, looks well-braced too. Does the transfer case spin okay in the Diff locked 4WD Lo position? It looks to me like in this position the rear output has a 1:1 ratio (same as 2WD), while the differential casing has a 3:1 ratio. I think that when the the differential is properly locked the casing and output should spin at the same speed.

I checked it last night and you're right; the diff locking does not work for 4Lo. The whole mechanism locks up as expected.

[gyenesvi]

I kike the effort for such realistic transfer case, but I don't get why a 2wd/4wd switch along with a central diff makes sense, maybe only marginally. The diff itself is supposed to ease the drivetrain when driving onroad, when it is not locked, but you can have a similar effect by using 2wd mode. I guess that is why real cars would typically use either of the two but not both mechanisms, as that may not worth the added complexity. For actual RC MOCs, I'd say the simpler the better :) So if you want some performance, then maximum 2 speed gearbox, and one of the two mechanisms is enough. For the building challenge sure I undertand it, but would rather reserve that for manual models.

Curious how the final model will turn out though, I like FJs too and plan to build more in the future :)

[damian_kane_iv]

14 minutes ago, gyenesvi said:

I kike the effort for such realistic transfer case, but I don't get why a 2wd/4wd switch along with a central diff makes sense, maybe only marginally. The diff itself is supposed to ease the drivetrain when driving onroad, when it is not locked, but you can have a similar effect by using 2wd mode. I guess that is why real cars would typically use either of the two but not both mechanisms, as that may not worth the added complexity. For actual RC MOCs, I'd say the simpler the better :) So if you want some performance, then maximum 2 speed gearbox, and one of the two mechanisms is enough. For the building challenge sure I undertand it, but would rather reserve that for manual models.

Curious how the final model will turn out though, I like FJs too and plan to build more in the future :)

My rationale here was to eventually use this T-case in my 4Runner MOC and aome 4Runner trims have a center locking differential with 4Hi/Lo modes.

I just wanted to create an all-purpose transfer case that I could easily use in both models. If I am successful, then I can just use a common architecture with some modifications here and there to get either a 4Runner, a Lexus, FJ, etc. 

Different models and years sometimes have the traditional part time 4WD and others have a torsen diff in the center

Im close to cracking the 4Lo locker. After that, Im going to try to rebuild this without a center diff.

 

 

 

12 hours ago, SNIPE said:

Great work, can't wait to use this in my ultimate 42177 MOD, but I will make it be 4 speed+DNR+HI/LO with the diff lock being a fully independent function

thank you, I hope my design helps you out and makes it into your model in one form or another

[rm8]

15 hours ago, damian_kane_iv said:

My rationale here was to eventually use this T-case in my 4Runner MOC and aome 4Runner trims have a center locking differential with 4Hi/Lo modes.

I just wanted to create an all-purpose transfer case that I could easily use in both models. If I am successful, then I can just use a common architecture with some modifications here and there to get either a 4Runner, a Lexus, FJ, etc. 

Different models and years sometimes have the traditional part time 4WD and others have a torsen diff in the center

Im close to cracking the 4Lo locker. After that, Im going to try to rebuild this without a center diff.

thank you, I hope my design helps you out and makes it into your model in one form or another

Only one 4runner have such complex transmission - 3rd gen: 2/4wd, lo/hi, central diff with locker - mix of full time 4WD and part time 4WD. 4 and 5 gen have different full/part time according to trim, but no more  "all in one" as before. Only Mitsubishi's with its Super Select still alive.

Such T-case looks really unversal for every life situation: fuel economy (really?), have some fun ( 2wd drifting on dad's car). safe driving (full time) and hard offroad (part-time).

I was always wodering, do sr5/trd offroad 4Runner owners substitute "part time" T-case with "Full time" from limited trims? Because Limited trim with chrome and sport-style low bumpers looks like common SUV from China.

 

[damian_kane_iv]

2 hours ago, rm8 said:

Only one 4runner have such complex transmission - 3rd gen: 2/4wd, lo/hi, central diff with locker - mix of full time 4WD and part time 4WD. 4 and 5 gen have different full/part time according to trim, but no more  "all in one" as before. Only Mitsubishi's with its Super Select still alive.

Such T-case looks really unversal for every life situation: fuel economy (really?), have some fun (sons 2wd drifting dad's cars). safe driving (full time) and hard offroad (part-time).

I was always wodering, do sr5/trd offroad 4Runner owners substitute "part time" T-case with "Full time" from limited trims? Because Limited trim with chrome and sport-style low bumpers looks like common SUV from China.

 

Honestly it would probably be easier to swap the bumpers, decals, and wheels from a TRD at that point lol

 

I was on some FJ forums and people were talking about the possibility of swapping one of those transfer cases from an old 4Runner into and FJ Cruiser since they all share a common architecture.

Probably on the rare side here in America though

Edited July 23 by damian_kane_iv

[lmdesigner42]

15 hours ago, damian_kane_iv said:

I checked it last night and you're right; the diff locking does not work for 4Lo. The whole mechanism locks up as expected.

That's too bad. I think the locking feature on your transfer case might work for 4 Hi though since the ratio is 1:1. Designing complicated transfer cases is fun, but it's hard to get the different gear combinations to work as desired. Real transfer cases let you cycle through the different modes by rotating a single input or moving a single lever, but Lego's options for changeover catches make that difficult to copy.

[rm8]

10 hours ago, damian_kane_iv said:

Honestly it would probably be easier to swap the bumpers, decals, and wheels from a TRD at that point lol 

true

Wife's father had 2000 4Runner Limited trim from US as reserve car next to another Toyota, sold it 8 years ago to buy RAV4. And now I regret that...Car was clean stock without road accidents...Fuel consumption was too much, but that truck can live forever

[damian_kane_iv]

12 hours ago, lmdesigner42 said:

That's too bad. I think the locking feature on your transfer case might work for 4 Hi though since the ratio is 1:1. Designing complicated transfer cases is fun, but it's hard to get the different gear combinations to work as desired. Real transfer cases let you cycle through the different modes by rotating a single input or moving a single lever, but Lego's options for changeover catches make that difficult to copy.

Yeah 4Lo locker needs work, but 4Hi locker does in fact work 

[2GodBDGlory]

19 hours ago, rm8 said:

Only one 4runner have such complex transmission - 3rd gen: 2/4wd, lo/hi, central diff with locker - mix of full time 4WD and part time 4WD. 4 and 5 gen have different full/part time according to trim, but no more  "all in one" as before. Only Mitsubishi's with its Super Select still alive.

Yeah, I saw a Mitsubishi Pajero iO while traveling this summer, with that sort of transfer case (2H, 4H, 4H Lock, 2H Lock, if I remember correctly). Pretty wild to have that many options! I seem to remember hearing that at least new Ford F-150 Raptors also had that sort of T-case--at least I was once convinced enough it worked that way to build a model like that!

My T-case certainly wasn't as compact as yours, though, @damian_kane_iv, so it'll be cool to see what you come up with!

19 hours ago, rm8 said:

I was always wodering, do sr5/trd offroad 4Runner owners substitute "part time" T-case with "Full time" from limited trims? Because Limited trim with chrome and sport-style low bumpers looks like common SUV from China.

Yeah, the Limiteds do look pretty awful! If one wants something that looks like that, why are you buying a 4Runner? I'd imagine few people would swap the full-time T-case into other 4Runners. Even if it is in some ways the superior system, I feel like most of the advantage is for people who can't be bothered to shift into 4WD, on paved roads (in bad weather), and I imagine most people enthusiastic enough to do a big swap like that would be the kind of people who enjoy shifting into 4WD, and care more about off-road performance than bad-weather performance.

I know for me, at least, locking hubs and shifting into 4WD is a sort of exciting ritual that I'd be sad to miss out on! (Especially with a proper mechanical lever for the transfer case!)

[damian_kane_iv]

On 7/24/2024 at 10:55 AM, 2GodBDGlory said:

Yeah, I saw a Mitsubishi Pajero iO while traveling this summer, with that sort of transfer case (2H, 4H, 4H Lock, 2H Lock, if I remember correctly). Pretty wild to have that many options! I seem to remember hearing that at least new Ford F-150 Raptors also had that sort of T-case--at least I was once convinced enough it worked that way to build a model like that!

My T-case certainly wasn't as compact as yours, though, @damian_kane_iv, so it'll be cool to see what you come up with!

Yeah, the Limiteds do look pretty awful! If one wants something that looks like that, why are you buying a 4Runner? I'd imagine few people would swap the full-time T-case into other 4Runners. Even if it is in some ways the superior system, I feel like most of the advantage is for people who can't be bothered to shift into 4WD, on paved roads (in bad weather), and I imagine most people enthusiastic enough to do a big swap like that would be the kind of people who enjoy shifting into 4WD, and care more about off-road performance than bad-weather performance.

I know for me, at least, locking hubs and shifting into 4WD is a sort of exciting ritual that I'd be sad to miss out on! (Especially with a proper mechanical lever for the transfer case!)

I totally agree with the sentiment. I only wish that I had a center diff too, so I dont destroy my front differential and CV joints when I try to turn 

[damian_kane_iv]

I also just put together some instructions for a version of this transfer case with a true differential locker: https://rebrickable.com/mocs/MOC-190822/dmj_brick/universal-technic-transfer-case-awd-2wd-4hi-4lo-center-differential-lock/#details

Edited July 29 by damian_kane_iv