dillon410021

I purchased my evo 9 last year from another state. The last owner had the dealer replace the rear diff under warranty because he though it was making noise but after that, it was still making noise. The dealer then replaced the transfer case and the noise was eliminated.

I have receipts for all the warranty work and the rear diff was replaced 17K miles ago. I was having a hard shift clunk so I bought a mustache bar and mounts for the rear diff and I was going to install them this last weekend as well as re-do the clutch packs in the stock rear diff so that it would work properly.

When i went to pull the rear diff, I drained the fluid and it was full of metal. I was opening it anyways so I was hoping it was the clutch packs breaking down but the amount of metal told different. I opened up the diff and opened the lsd unit and found the problem.

Photos are below in post!!!

The pinion shaft and pinion gears were very worn and mostly broken. The pinion shaft holds the 4 pinion gears. Two of the gears had broken away from the pinion shaft and one gear was chipped. It was all stuck in the lsd unit so it couldnt go anywhere but wear down and cause metal shavings. The inside of the lsd unit was worn from the 2 sides of the pinion shaft that broke off.

My question is how does this happen? The car made no noises when driving or anything. I was told the fluid used before i bought was Redline shockproof (which has been known for ruining transmission but is made for diff's). Could the Redline shockproof cause this damage? Maybe low fluid level even though i drained what looked like the right amount. It could also be a bad part from the factory even though this diff only has 17K miles(not sure if new or refurb).

I now need a new rear diff or atleast the lsd unit.

I dont beat on my evo much at all. I daily drive it. The previous owner took care of it as well.


Any and all help is appreciated! Thanks

xXANCHORMONXx

iTrader: (15)

Redline is so good it makes broken **** work.. Lo

It was probably launched or something like that.

Can't trust anyone these days

X Double Dot

Looks like the spider gears seized on the pins, are there any other signs that the diff may have been run low (or without) oil?

Also, I'm not sure if redline shockproof is LSD safe without friction modifiers in there. doubt that that caused the failure, but I'd imagine the LSD wouldn't work as intended (even less considering the plate arrangement).

dillon410021

update: I bought a used diff and installed 12 plate setup and oem fluid. waiting to test as my local shop messed up my brake rotors letting a rookie turn them.

drive955i

iTrader: (6)

I had Jon at TRE rebuild and upgrade my rear diff and he tore it down as soon as I brought it in. My spider gear pins were beginning to gall. I noticed no effect from the driver's seat, and who knows how far gone it could have gotten before I noticed anything without the rebuild. I feel for you. I'd say poor clearance specs from the factory, and maybe a poor installation at the plant, contributed to your diff's early demise. Let's hope this issue is an anomaly, and not the norm.