Hey guys,

In need for a new center diff as i found out mine is on its way out.

Dont have much knowledge on diffs but been reading on them .. Would it be good to upgrade to a 12kg or 20kg STi diff, or should i just replace it with a stocker?
Is it even possible to fit a STi center diff to my g/b?
Does how much power im making have any effect on the center diff?


Let me know what you have guys.

Any help would be much appreciated.



-Nick
0432154862

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"Wrong fitment".

I have a centre diff to suit late type 5 speed. Got nothing 12 or 20 KG though.
Who told you the centre diff was on it's way out?
Let me guess, you had the car dyno'd at ASG and they told you it was stuffed?
Unless your car has been towed wrong, or run with mismatched diff ratios, it's unlikely the centre diff will in fact be stuffed. It seems to be something the hub dyno can't deal with, but in reality on the road it'll do nothing wrong.

Edit; Ok, Just read your other post and I can't see how a centre diff can make a whining noise? There are bearings around that area but while travelling in a straight direction (at any speed) the centre diff is not doing anything, it's gears are stationary. There is no hypoid in a centre diff, so it's unlikely changing the 'centre diff' will fix your whine. Maybe a bearing in the transfer section.

Hey,

I first noticed it when driving at high speeds (alot of freeway driving sitting on 100) and it slowly got a little louder. Then started hearing weird geary noises when slowing down either in gear or in neutral. Car still drives fine with no problem shifting, just the whining. Car has always been towed via flatbed.

I took it to ASG today and they had a listen from under the car while it was being run on the hoist and informed me that its most likley the center diff or something in that area atleast, towards the rear of the g/b.

I have been reading on rexnet and people with busted center diffs have been experiencing clunking when turning, which i dont get, that i know of.

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"Wrong fitment".

OK, I think 'centre diff' is a term people wrongly use to describe the entire transfer section of the gearbox. There is a centre viscous coupling in there, bearings and a pair of transfer gears that reverse the direction of the tailshaft to the front diff pinion. The transfer gears are helical cut so they will load one bearing on acceleration and the opposite on deceleration, the gears themselves may be causing the whine. A transfer section from another box would quite possibly cure the whine. There are several different types though. Any box that has 4.11 or 4.44 gears will have 1 to 1 transfer gears (31 teeth each side) but 3.9 Aussie boxes have 30/33 teeth and are not suitable. Also some have ball bearings, some have tapered roller bearings, doesn't really matter if you swap the whole lot over but you can't mix internal parts from each type. Also the transfer case should be off an 8 bolt box, early boxes are different again. Someone should have a broken late model 4.44 they will sell you cheap?

Told ya Doug knows his shit Nick. Even guessed how it was diagnosed!

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No more GC8, sad face.
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