Jdm Transferr Cases

[pimpin81]

Are they compataible with usdm eclipse gsx's?

I was wondering because i got one with the same spline count with my jdm engine and transmission.


I herd a rumor that the gear ratios can differ.. is this true ?

 

[Usatuff]

Aslong as it is the same ratio as the rear I believe it will work. If they are two different ratios then 1 of the two will need to be changed

 

[pimpin81]

how does one determine if its the right ratio? the transmission i believe came from a Mitsubishi rvr and that tansfer case was attached to it when i received it from the importer. It was after i realized the transmission was useless, unless someone with experience in transmission rebuilding could swap out the ring and pinion gears which would change the final drive ratio making it compatible..


But without knowing i put the jdm transferr case on because there was no common information stating that the transfer case had a gear ratio of its own, which i in turn thought the ratio in the transfer case would be dependent on the transmission.. and the spline counts matched.


So Now i have drive train noise coming from the front portion of the engine bay which I'm getting diagnosed by a shop on Monday.. so if i could get some information on how determine if the transferr case has the proper ratio i could relay it to the shop I'm having put the stock transfer case back on .

At idol you would not know anything is wrong at all, but revving the engine with clutch in or out makes a horrible noise which i cant really describe .and while driving down the road it sounds like the transmssion has no oil in it and the gears a " wineing". ive ask many people what the prolbem could be but have recived no difinitive answer. So hopefully this shop im sending it to is compitant enough to figure it out .

 

[Usatuff]

The Tranny and TC are matched, The tranny outputs to the Front CV shafts and to the TC which sends through the drive shafts to the rear wheels. Say your Tranny and TC have a 3.5-1 gear ratio meaning that for every engine RPM sent to it the FRONT CV shafts make 3.5 turns, if it doesnt match the rear which say has a 3-1 gear ratio , meaning the rear wheels want to only turn 3 times per RPM, but are being forced to turn 3.5 times as they are ? Since the cars have a limited slip centre diff it will allow the rears to catch up, but it "slipping" will create heat over time and burn the centre diff up. Kinda similar as to why you can't tow an AWD car on a regular tow truck, you can raise the friont wheels and not have them turn and the rear wheels will roll causing the driveshaft to spin but the centre diff will break

To check the rear gear ratio jack up the rear and put on stands. mark on the driveshaft your start. spin the tire by hand and count how many times the tire fully rotates before the drive shaft has completely spun around. If you can spin the tire 3 times and the drive shaft made a complete turn the you have 3.00 gear ratio. If you turn the tire almost 4 full rotations but not quite then it could be 3.91 gear ratio. i think it is the same way for the front but i am not %100 sure

 

[pimpin81]

so what your saying is , if the jdm transmission has a 3.9x final drive ratio then the transfer case will have that same ratio..?




if so, is it possible to make the jdm transfer case compatiable? my car should have a 3.545 final drive ratio.

The jdm transmission however which im not using should be 3.91 final drive ratio. and i unknowingly used the jdm transfercase because i thought there ratio was dependent on the tramsnisson!!! so that being said my center diff could be shot. what kind of noise will that make ?