924Board.org

doolie72 · Joined: 01 Dec 2018 Posts: 27 Location: California, USA

Hi all,

I have an original ZF LSD straight outa 931 snail shell trans. I'm looking at installing it into my 1980 931 but not sure of the procedure. Looks like it can be done without dropping the transaxle, but I'm assuming I can't just throw it in without some sort of shimming. If anyone knows how this is done I'd love to know!

Cheers

Jim

Cedric · Joined: 27 Aug 2004 Posts: 2608 Location: Sweden

Do you have acess to the factory manual? Its all in there.
_________________
1980 924 Turbo
www.instagram.com/garagecedric/

doolie72 · Joined: 01 Dec 2018 Posts: 27 Location: California, USA

Cedric · Joined: 27 Aug 2004 Posts: 2608 Location: Sweden

If you keep the ring and pinion, in theory you should only need to set the bearing preload. But its a bit tricky to measure as you can see in the manual, and you might need different shims to get it right.
_________________
1980 924 Turbo
www.instagram.com/garagecedric/

kevingross · Joined: 15 Apr 2015 Posts: 34 Location: Stow, MA, USA

You need to re-establish both the differential carrier bearing preload (turning torque) and the ring-to-pinion backlash. Both are critical to the longevity of the associated parts. Which is to say, done wrong, stuff breaks.

The factory workshop manual can be a bit cryptic, but it does explain the procedure. I use the original tools to do this work.

Good luck!
_________________
Kevin
Catellus Engineering, Inc.
http://www.catellusengineering.com/
catelluseng@gmail.com