Ok, So had an interesting trip to the shops today. Car was driving fine until I got to the car park. I saw a car leaving so I reversed to let it out. When I did my newly rebuilt LSD :-( shuddered a bit in reverse. After leaving the shops the diff now whines quite loudly on deceleration. Any ideas? Its a long shot but would changing the oil help? The diff is running Fuchs ls90 at the moment. Thanks in advance for any help..
Is that oil rated for LSD use? Diff shudder isn't unheard off with a new LSD, especially one that is tightened properly when turning corners. My diff guys always gets people to do a couple of complete 360° turns each way to get the cones to slip and work some oil into them. Did you fit new gears or re-use old gears? Old gears can whine a little as it's very unlikely that when the diff is rebuilt that it's set up exactly as original so the gear mesh will be slightly different so the wear point will have changed a little.
As far as I know the oil is rated for LSDs. We rebuilt the diff with the old gears (new bearings seals etc) about 4 weeks ago and its been fine, just had a bit of shudder in reverse on the odd occasion. Apart from that its been great. I just think its funny there was no whine before, and instantly after a little shudder in the carpark its there. I also just took it for a quick drive around the block and it was quiet for about 5mins before it started making noise. Cheers.
Take it back and see what they say. Sounds like something has gone wrong. Could possibly be a lubrication failure if it's fine when cold but starts to get noisy once it warms up. My diff guy recommends a 80w-140 for the diffs that he builds.
Ok so looks like we've solved the problem. Somehow the pinion preload became loose, so after throwing the car up on the hoist, dropping the tail shaft and re tensioning the pinion preload the diff is nice and quiet again. I think I will change the oil though.
