GC8 with STI 6 Speed - loss of drive

Skyward
Learner Driver
Posts: 11
Joined: Sat Sep 17, 2016 10:44 am

GC8 with STI 6 Speed - loss of drive

Postby Skyward » Sun Dec 17, 2017 2:01 pm

Hi All. I recently fitted a sti 6 speed (2001 model) to my 98 gc8. The following is what I installed:
6 speed box
Wrx auto tail shaft
Matching 3.9 R160 rear diff (open)
New stage 2 competition clutch
New competition clutch lightened flywheel

The install went really smoothly, no problems and I ran it for about 500klm and was loving it. THEN...

Since it was a nice day out I took her out for a spin. I took off harder than normal, but didn't quite dump the clutch and all of a sudden I lost MOST of my drive. It feels as if the clutch is slipping (but I don't think it is) and drive is being lost. I can still select all gears and I can move but takes a while to get going because of all the slipping/loss of drive. My guess is maybe centre diff let go?

If I give it some gas, the revs will build and I can hear a grinding noise. I don't think it's gears (fingers crossed - it is a 6 speed after all) as the problem is the same regardless of what gear I'm in.

Hoping someone can diagnose. I'm shattered to think about pulling the box out again. Maybe a job for URD... *Sobbing...

Skyward
Learner Driver
Posts: 11
Joined: Sat Sep 17, 2016 10:44 am

Re: GC8 with STI 6 Speed - loss of drive

Postby Skyward » Sun Dec 17, 2017 5:01 pm

So on closer inspection, it would appear that the LHS rear shaft has popped out of the diff.

I retained my original MY98 shafts, which after a bit of googling may be the problem. Something to do with the location of the C clip on the shaft. I may have to get a MY99 LHS shaft. That's if I didn't root the diff...

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matto20v
Impreza RS Driver
Posts: 169
Joined: Wed Mar 07, 2012 11:06 pm
Location: Perth, WA

Re: GC8 with STI 6 Speed - loss of drive

Postby matto20v » Sat Jan 20, 2018 8:13 pm

How did you go with this, is the diff OK?
MY00 GC8 (Limited Edition)

Skyward
Learner Driver
Posts: 11
Joined: Sat Sep 17, 2016 10:44 am

Re: GC8 with STI 6 Speed - loss of drive

Postby Skyward » Mon Jan 22, 2018 8:14 pm

Yeah diff all good. I found that the shaft had broken (sheared off) where the C-clip sits. The shaft had popped out and because the diff was only grabbing 3mm of shaft, it broke. I put a correct shaft in (MY99+) and all good again.

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