Little background on this car bare with me as this will be a little lengthy.

I Bought the car (05’ Evo 8) as a roller May 2024, built a 2.4L put a used 5speed trans in with a supposedly jacks built Non-acd t case w/ factory front lsd diff which was taken apart but local shop for inspection of bearings and gears before installing. Has a comp clutch sprung stage 3 clutch, act monoloc retainer clip.

I’ve put around 500 miles on the car since I’ve gotten it put back together trying to work out any issues and bugs.

So this is the second time this happened. Backing into the garage snow on the ground as soon as the rear wheels touched the dry concrete the front wheels spin in the snow and no power to the rears along with a grinding noise. Coast out it of the garage and put it into 1st to try to get it to move and all I get is a grinding noise with little to no power output to the wheels no matter how high I rev the engine. If I let it idle in gear giving it little throttle and clutch slippage and travel about 5-15ft in a straight line it’ll act normal again and the noise will go away.

ive already put the car up in the air trying to diag the issue with it idling in every gear. All the wheels spin in the same direction.

I’m beyond confused at this point since this morning I verified that it is powering the rear wheels when I got it to kick the *** end out when turning in the snow onto the main road.

Seems like the issue only persists when backing up and there is a traction difference between the front and rear wheels.


I also get a click/knock sound when backing up and slipping the clutch at low speeds which sounds like it’s coming from underneath (only in reverse.)

at this point I’m wondering if it is either the center diff or viscous coupler giving me issues when backing up and I get a traction difference. Going forward I don’t have this issue when the front wheels hit dry concrete and the rears are still in the snow/wet road or gravel.


any insight or advice on where to look or personal experiences of the same issue would greatly be appreciated.

 

inspect the center diff. theres a rectangular plate you can remove to get a better look

 

the black plate bolted at the bottom of the trans casing is what you’re referring to? Thought that was just to remove the reverse gear.

thanks for the reply.

 

not trans. center diff


this one one is upside down, and shows am aftermarket cover with heatsink feature. its normally just a steel plate

 

thanks for the reply,

but isn’t the front diff located in the transfer case which you have pictured and the center diff in the trans? Or are you referring to the ring and pinion in the transfer case?

if that’s was damaged wouldn’t I have a issue all the time traveling forward or backwards and not just reversing and having a issue when there is a traction difference between front and rear wheels?

I mean I suppose it wouldn’t hurt to take a peek in there. It looked brand new 500 miles ago when it was disassembled for inspection.

 

you said youre wondering if its the center diff. I say go take look since youre already under there. i'm not sure but i think youre mixing up the terminologies.
I cant tell what exactly is the noise and power-to-the wheels youre describing. maybe you can try again
I have broken many things so I'm trying to remember how those felt and sound like. breaking the output shaft, I cant move the car at all, bit of grinding. exploded clutch, cant remember. cracked trans cover, leaking. broken rear axle (never had cv issues) the car moves slightly. chewed up TC R&P, moves normal but not far until a shrapnel gets into the teeth.. this feels like rear brake were engaging. i know i wasted too much time investigating the rear

 

Yes this is correct. Often mixed up. Here is a good video explaining and identifying the different trans and transfer case components:

 

did it cover the center diff? I actually didnt know there another "diff" between the TC and transmission. All i see in there are tubes. is there some kind of R&P in there?

 

the front diff is in the TC inside the diff housing. The acd plates/ viscous coupler (depending on which t case the car is equipped with) is attached to the diff housing which is then connected by tubes going into the trans to the center diff.