Limited slip differential repairs

mattay · Postby **mattay** » Wed Jan 23, 2013 3:04 pm

I was wondering if anyone has any recommendations for places to get a Limited slip differential repaired. I'd prefer a shop in brisbane or in the region.

My differential is in need of maintenance. Its a LSD of some sort installed by the previous owner and unsure what type it is but I suspect that is RX7 clutch type. Or as I like to describe it as a no slip diff, as it is either locked or it is not, there is no slip. It is very abrupt in releasing the energy in the drive train when when the clutch is disengaged. Its great on the track but not in the pits or car parks and would like it fixed.

I have not opened the diff up yet to inspect it. But I suspect that I'll need some machining done.

hks_kansei · Postby **hks_kansei** » Wed Jan 23, 2013 4:50 pm

What's it doing that makes you think it needs repairs?

If it's the chirping/locking it may not be a fault, it may just be an issue of adjustment (if it's a clutch pack diff)

Are you sure the previous owner didn't just weld the diff?
If that's the case you'll need to replace the centre since you can't really un-weld a diff.

project.r.racing · Postby **project.r.racing** » Wed Jan 23, 2013 5:13 pm

if it goes on and off, it ain't welded.

Postby **NitroDann** » Wed Jan 23, 2013 5:22 pm

I lot of them go on and off harshly, thats just how it is in hardcore race parts land.

Dann

flycasta · Postby **flycasta** » Wed Jan 23, 2013 6:26 pm

The way you've described its behaviour it sounds like its welded. Does it open up at all or just seems locked the whole time?

Hellmun · Postby **Hellmun** » Wed Jan 23, 2013 7:38 pm

mattay wrote:I was wondering if anyone has any recommendations for places to get a Limited slip differential repaired. I'd prefer a shop in brisbane or in the region.

My differential is in need of maintenance. Its a LSD of some sort installed by the previous owner and unsure what type it is but I suspect that is RX7 clutch type. Or as I like to describe it as a no slip diff, as it is either locked or it is not, there is no slip. It is very abrupt in releasing the energy in the drive train when when the clutch is disengaged. Its great on the track but not in the pits or car parks and would like it fixed.

I have not opened the diff up yet to inspect it. But I suspect that I'll need some machining done.

Before you spend a lot of money having it un-shimmed by a diff specialist you may just have the wrong oil in it. Clutch pack diffs required friction modified oil or they will behave like you say, completely on/off. You can buy LSD additive by itself and just add it to the existing oil, I used a penrite product for mine. If it's on/off it's not a locker.... locked diffs only chirp tyres, clutch packs will also chatter in the diff when on full lock (sounds very different to tyre screech, more ceramic). Put it in gradually though, it takes a long time to undo excessive friction modifier before it'll lock up nicely again.

mattay · Postby **mattay** » Thu Jan 24, 2013 12:57 pm

Thanks for the feed back guys.

I lot of them go on and off harshly, thats just how it is in hardcore race parts land.

This is very unpleasant as the car is street dríven more than its track dríven. The previous owner had modified the car for 2F racing and a street registered car, before loosing interest after 2 event after having electrical issues.

Hellmun you describe the its characteristics best

clutch packs will also chatter in the diff when on full lock

. The chattering is very harsh like the diff wants to tear its self from its mounts. After I purchased the car one of the first things I did was to replace the the diff oil with a synthetic LSD oil but it didn't seem to make a difference.

I'll need to open up the diff to find out what type it before making any decisions.

Hellmun · Postby **Hellmun** » Thu Jan 24, 2013 8:46 pm

Just get something like this http://www.amsoil.com/shop/by-product/gear-lube/slip-lock-gear-oil-additive/. Add enough and you'll basically put it back to an open diff. I'd be pretty confident it's a clutch pack if the diff itself is chattering, torsens/lockers/eletronic diff won't. I put about 1/3rd of a bottle of the penrite branded additive in my diff to reduce some push understeer on the track and it worked a treat. I basically just put a coke bottle cap worth of it in, drove it for a week and kept adding until I was happy the locking had been reduced. If you stuff it up you just have to change the oil again and wait for the additive to wear out of the clutch plates.