1986 Turbo LSD rebuilt issues... May be useful for someone...
05-16-2016, 11:09 AM
#1
Rennlist Member
Thread Starter
1986 Turbo LSD rebuilt issues... May be useful for someone...
1986 Turbo LSD rebuilt issues...
So opened the 260k+ transaxle with the view of rebuilding the LSD (016R 5P) A few surprises. The box was pristine. No discoloration or wear stains on any teeth - gears and pinion/crown. Bearings - all except one perfect. Seals - all perfect. An amazing result for a box with kind of unknown history and already on 10-odd races. It has never been opened either - the seals had marks dating them to late 1985.
Total parts needed - pinion shaft bearing was beginning to go as we noted discoloration, but I cannot complain and the synchros for 3-4th were also on their way out. but still in tolerance. Changed the input and output shafts seals, as well as the plastic cap at the end.
Started to rebuild the diff. The friction discs and the cone washers were shot. Ordered new friction discs - originals are NLA as my gearbox came with the 917 PN from the factory. The new 951 PN friction discs are 0.4mm thicker each! Add the "thicker" conical washer and the preload on the diff increased so much that we could not get it to break away even using a 1mm long pipe. Ultimately had to resort to taking away 0.1mm off the splined discs (original thickness 1.9mm) to make the diff work. When we tested it, the preload was in the region of 65ftlbs. Almost double the factory setting...
Not bad for an out and out racer, but not sure for a street car.
Anyone else encountered this "problem"?
So opened the 260k+ transaxle with the view of rebuilding the LSD (016R 5P) A few surprises. The box was pristine. No discoloration or wear stains on any teeth - gears and pinion/crown. Bearings - all except one perfect. Seals - all perfect. An amazing result for a box with kind of unknown history and already on 10-odd races. It has never been opened either - the seals had marks dating them to late 1985.
Total parts needed - pinion shaft bearing was beginning to go as we noted discoloration, but I cannot complain and the synchros for 3-4th were also on their way out. but still in tolerance. Changed the input and output shafts seals, as well as the plastic cap at the end.
Started to rebuild the diff. The friction discs and the cone washers were shot. Ordered new friction discs - originals are NLA as my gearbox came with the 917 PN from the factory. The new 951 PN friction discs are 0.4mm thicker each! Add the "thicker" conical washer and the preload on the diff increased so much that we could not get it to break away even using a 1mm long pipe. Ultimately had to resort to taking away 0.1mm off the splined discs (original thickness 1.9mm) to make the diff work. When we tested it, the preload was in the region of 65ftlbs. Almost double the factory setting...
Not bad for an out and out racer, but not sure for a street car.
Anyone else encountered this "problem"?
05-16-2016, 04:55 PM
#2
Rennlist Member
Yes, that is a very common problem. I have two options available to fix the issue: new 2.0 mm friction discs or I can modify your thrust rings to work with the new 2.5mm friction discs.
Let me know.
Let me know.
05-17-2016, 04:42 AM
#3
Rennlist Member
Thread Starter
We fixed it by skimming the original thrust rings to 1.8mm thick. Nicely preloaded now...