Shortly after our most recent trip to the dragstrip, our Stage 2 shop car started developing an odd clunking noise from the rear differential. The rear end would also bind terribly during tight turns, nearly stalling the engine in the process. Upon draining the rear differential fluid last, we noticed a good deal of metal shavings around the magnetic oil plug. Changed over to redline Shockproof to see if the clunk/bind would go away. No luck. Still there and it's gotten progressively worse in the last few days. Turns out that the rear clutchs are warped from the 550+hp launches. I suspect bouncing up and down off the ground, with the wheels spinning like made, did the rear differential in. Will be installing an upgraded differential this week and will report the findings.

Cheers,
shiv

 

Man that sucks, I thought the evo was the best drag car eva!

 

What is the make of the upgraded differential that you guys are going to install?

 

Drag racing is a great way to quantify power output (especially for all the DD naysayers), but it is Hades on an AWD car's parts. Very sorry to hear that happened to you.

 

Ah, the beauties of drag racing... Doesn't teach you anything about tuning, destroys parts on your car, and lasts a few seconds per run

We'll be putting in a Cuscu clutch type LSD this week. Should be capable of handling a bit more power without warping. Probably a good idea to run Redline Shockproof from the start. This might have prolonged the life of the stock diff if we had done this from the start.

shiv

 

Be careful with the Redline Shockproof Shiv, the racing world doesnt agree with using it in the rear diff - especially a clutch type. Ever try the Silkolene lubes? Let me know if you are interested

 

Learn something new everyday..

Never tried the Siklolene stuff. But I'll use it if you recommend it.

shiv

 

Silkolene BOA 90LS

This stuff is liquid gold baby! I'll get some coming your way

 

How much are they and how do you order them? That page didn't provide any link to buy.

 

Yep...shockproof and rear clutch LSD is a big no no...although regular Red Line 75w 90 will be ok

 

superz has been running shockproof in Evo rears when some LSD additive is added in, he has said it works pretty well. I am running 75w90 Redline right now. Hey Shiv, does it clunk all of the time or just every now and then? My rear will clunck occasionally when I am pulling out in reverse, but not very often and I have not drag raced the car. Just wondering if an occasional clunck is normal or indicitive of a problem.

 

Oh that's normal. My WRX did that to. It's the center diff doing the noise. It is also a limited slip unit and needs to build up friction when going in Reverse.

Eric

 

Thanks Eric, I really have not been worried about it at all, but when someone like Shiv posts up a potetial problem then I listen as he does not seem to be one who posts about little b/s crap problems.

 

Oh Ya when Shiv posts I listen. It seams like he has the noise when you lays the power down when the limited slip is required to go into action.

Hey Shiv,

Sorry to hear that man. I hate when I brake parts. But at least you did it in full glory not some kind of wimpy way. YOUR THE MAN!

 

Clunks every now and then are normal with clutch-type rear diffs. What has happened with our car is quite a bit beyond normal klunkage. Imagine the inside wheel skipping (locking and rolling or locking and rolling) during low speed cornering. And unless the revs are kept up, the binding will stall the engine.

clunkin' away...
Shiv