Alex Sol

I replaced the seal in the final drive and it was pretty straight forward job

With transmission out of the car and full of oil:

1. wrap the nut on top of the transmission as it is some kind of breather (???) and leaks oil all over when transmission laid on side

2. screw in two half shaft / axle bolts into the final drive half shaft (side 1)

3. use a long box wrench and place over one bolt, then leverage other (these single use hex bolts are paper weights anyway... ) to counter hold while removing the long bolt 17mm or 19mm head M10 bolt (from memory) in middle of final drive. mine came off with a crack which suggests they were loctite in place

4. carefully remove seal - using seal remover - i used pry bar and lightly tapped while being mindful not to mark the race - i scratched the hell out of the race though... so sanded lightly and put lots of Curil T

5. replaced seal by pressing the seal on part way and tapped in with block of wood

6. do same on other side

QUESTION; in the Bentley manual, there is a torque spec for front final drive on C4 around 32 lb-ft and no mention of loctite

Does anyone know the proper torque specs?

Alex Sol

Reason or replacement? Looking for oil leak and related soil that builds up / sticking to said oil...

I believe i found the culprit. When i removed the final drive, the seal was extremely dirty and dry and hard... like a lot of the rubber bits on my 964

Rocket Rob

Yes, the transmission has a vent on the top.

As for the torque, according to the workshop manual, the hexagon head screw/half shalf flange (M10) bolt torque is 32.5 ft-lbs (44 Nm). No mention of loctite.

mystert

Be careful tightening it. The bolt is the same size as the axle shaft bolts but has approximately half the torque specs. I got the wrong spec and stripped the bolt out. Ended up having to take the differential out and replace some parts inside it.

Alex Sol

mystert, i pity the fool that had to take out differential!

thanks Rob for the torque spec. i forgot i have the manual and didn't check. thanks for confirming!

the vent would explain the hole in the nut... and all the oil that spilled when tipping over the transmission

mystert

While I was in there replacing the stripped nut, it gave me an excuse to replace the LSD friction plates ................

Alex Sol

eric,

you must tell me about the lsd upgrade.. how does it feel on daily driving? how does it feel at the limit?

do you track your 964?

interested...

mystert

I replaced the 20+ year old burnt planes and friction discs with new ones, changed the fluid with delvac, and added in a bottle of GM limited slip additive. It chirps the tires on low speed turns more often. It also feels more under control in turns at higher freeway speeds. All in all it feels better. I do not track team car just yet. I have a friend that keeps bugging me to go to one of the local Porsche auto cross events and will probably go once I've got a few other things sorted out on the car. All in all it was pretty easy to do and wasn't that expensive since I had a 2 plate LSD.

Alex Sol

mystert - sounds like you have to push the 964 a little harder to feel the difference. i agree with your buddy to get out to some performance driving events....