What the F&@% is up wit my tranny

[prodsm]

Ok I have a JDM MANUAL tranny installed on my 90 tsi awd,

My fluid is: Gm syncromesh
My clutch is: Stock

Ok everytime i let off the gas, i feel my tranny shake pretty bad somtimes.
My car sort of rattles, like when ur cruzing in 1st gear and u let off the gas, except it happends pretty badly in every gear. I also have a little grind in 3rd gear nothing big, somtimes its hard to shift into 2nd but not to bad.

1) what do u think is the matter?
2) will the clutch adjustment (under the pedals) mod help.

Thanks
G

 

[Lucky13]

Are you using a US or JDM transfer case? How about the rear end? JDM tranny's come with a different final drive then US ones. This may be part of your issue.

 

[98RedGs]

Moved to drivetrain/tranny.

Also lucky sounds like he's thinking in the right direction.

 

[prodsm]

Ya im using my US transfer case, but i dont think thats the problem. Wouldent the car be un movable if the ratios were different. My car moves perfectly it just shakes when i let off the gas in every gear.


Thanks

 

[RipperXX]

Yes and no.


If the gear ratios are deferent in the front and rear I'm betting it would cause an effect like that.

Also where the hell did you get a JDM tranny? Out of an Evo 3??? I ask because I am looking for a JDM tranny.

 

[prodsm]

I got a Jdm tranny when i bought my JDM motor. They have dual syncros and are a bit stronger then the USDM trannys from what ive read.

Ok so back to my problem, is it a big deal or will it #### me up in the end. i can live wit the shaking if its not doing any harm. I also have the JDM transfer case if i need to reinstall it.


Thanks

 

[DSMJim]

Are you using a US or JDM transfer case? How about the rear end? JDM tranny's come with a different final drive then US ones. This may be part of your issue.

This isn't my area of expertise however im going out on a limb here thinking that if the gear ratio in the JDM tranny was different but you were still running the same rear end you would just end up with a slightly modified gear setup. The power comes out of the tranny the same however the length of the gears would be a sort of hybrid type as the rear end is for use with the US trans but your using an EVO trans with slightly shorter gears. Can't see any issues mechanically with that.

Are there any US/JDM tranny experts willing to give us the definate answers?

 

[Omega]

What do you mean that the trans shakes? Does the shifter move? If you are using the correct trans/transfer case, I would lean more towards bad engine bushings/missing bolt(s).

 

[RedAllWheel]

The JDM trannies have a different final drive ratio than the US trannies and they don't mix well with the US rear because of this difference. So what happens is the center diff takes in the added stress and eventually gives out and explodes. I know this because the first time I seen a diff grenade because of the JDM swap the kid welded the diff, put the trans back in his car and it didn't want to move, you could literally hear/see the wheels skip while driving strait because of the different ratios. I don't think thats the problem your having with vibration... It sounds more like a bad carrier bearing in the driveshaft, or a bad transfer case.

 

[prodsm]

so in other words, i should put in my JDM transfer case?

 

[prodsm]

I have also noticed some oil leaking out of the rear diff.

 

[RedAllWheel]

Give your driveshaft a tug to see if their is play in the carrier bearing, then try a different transfer case.

 

[prodsm]

Ok, ill try to tug on the drive shaft and see if theres any play, what should i do
about the small oil leak at the rear diff?

Thanks

 

[prodsm]

No play in the drive shaft, um but there is still this slight oil leak at the rear diff??

 

[RedAllWheel]

I would give the rear a quick eye inspection, wipe it clean... then pull the cover off and look for damage internally, if nothings wrong inside reseal the cover and fill with fresh fluid. Keep in mind this could be the source of your vibration problem also