04-29-2005, 12:31 PM
"Borrowed" this from 968.net
tsj919 Wrote:This is the what i did to replace my stock open diff with a optional torsen LSD in my 6 speed 1993 968.
1. Remove cat-back exhaust.
2. Remove both drive shafts.
3. Drain gear oil.
4. remove the stub axles and side cover from the transaxle.
5. Now the diff will pull right out, but be careful cause it is heavy.
6. Pull the bearings from both sides of the diff taking note of the shims under each bearing. i used a good gear puller from sears.
7. Find a good way to hold the diff while you use a big air wrench or a large breaker bar to remove all 12 ring gear bolts. my neighbor has a very solidly mounted large vise that worked great.
8. Now I assumed that the gear backlash was set correctly with the old diff. so i took both of the diffs into work where we have some precision measuring equipment (+/-.00005"). taking several points on each surface we measured the distance between the bearing surfaces and the location of ring gear mounting surface relative to those. We did this on both diffs and calculated what shims i would need to make the new diff the same width (between bearings) and to have the ringgear surface in the same place as before. so then i ordered the new shims i would need and 12 new ring gear bolts.
9. Now you have to solidly hold the diff while you torque the 12 ring gear bolts up to 150 ft-lbs (i think), the same neighbors big vise worked great for this.
10. Press the bearings back on with the correct shims, i reused my same bearings cause i wasn't sure how to get the races out of the cover and tranny case and they looked great and spun free. i put the bearings in the oven at 250 degrees while the diff was outside in the winter. with this the bearings went on easily with some light tapping from a hammer and chunk of 2x4.
11. Put the diff back in the tranny, put the cover and stub axles back on, put the drive shafts back on, and put the exhaust back on.
12. refill the tranny with some mobil 1 gear oil, the torsen diff is all gears so no LSD modifiers are needed.
13. enjoy your new 968. my 968 is a totally different car, your can launch it better and get on the power sooner coming out of corners instead of just spinning the inside wheel. and you can do some pretty good cookies with both rear wheels broke loose.
sorry if i missed any steps. It's been over a year since i did mine and haven't had any problems.
If you don't count the cost of the diff i think i had less than $100 in parts. $48 for new ring gear bolts, a few bucks each for the shims, gear oil and new hardware to replace the rusted exhaust hardware that was removed with a hacksaw.