Nowanker

I can't recall ever seeing a thread about it, and search function here is pretty much useless, so please forgive me if this has been covered...
Anyone here ever rebuilt their LSD?
Last time at Laguna I had wheelspin issues out of 11, and this morning I had one rear wheel on a wet drain grate and the car wouldn't even move.
Looks like GM sells a clutch pack kit for around $100/side. Any aftermarket upgraded clutch packs available? A Quaife LSD is available for ~$1500... anyone with any feedback, or have have experience with any other aftermarket option?
Thanks!

meanjoe

MTPZ06

Curious....how old is the fluid in your diff, and did you also add the limited slip additive?

Josh B.

Interesting that you're having issues, doesn't come up as an issue very often. Back in my mustang days I would recommend just repacking a traction-lok diff instead of buying a more expensive one. They have friction material by design and those friction discs wear. Since you track your car, maybe a Quaife is right for you. If mine ever wears out, I'll repack the stock diff.

sccaGT1racer

Yes I have rebuilt them. Its not a tough job but some special tools are required or improvised.

C6_Racer_X

$100 for a clutch set isn't bad. I completely wore out the diff in my wife's MB 560-SEL recently. Friction discs for that one are ~$90 each (there's 6 of them) and the steel discs between them are ~$60 each.

Replacing the clutches isn't a terribly bad job. Pay attention to detail. Keep track of all the shims and washers when you take it apart, and get everything back exactly where it was. New seals are generally a good idea as well.

If you want to refresh/replace the bearings, then it gets more complicated. That's always a tempting thing to do, but it usually isn't necessary. Unless there's obvious play, resist the urge to mess with that.

Nowanker

I bought the car with ~40K on it, and it had been tracked 'some' before I bought it. Haven't measured the breakaway torque, but yesterday in the driveway said there was definitely an issue.
Surprised it hasn't come up before. Recall a post from LG talking about rebuilding their race car diff every (other?) race. Posted this in the race/autocross section too, with zero response so far.
Not concerned about the process... 40 years now as a tech, doing diff work is unpleasant and smelly but not impossible. Just curious as to other options from stock, or feedback on a Quaife, etc. The ~$100 clutch pack is X2, for both sides.

Nowanker

Diff fluid is recent Redline. Comes with some friction modifier already, so I didn't add any more. Seems it doesn't need any at all!

LS1Steve

Fluid is recent, as is the start of the issue... So, first thing I'd do is swap the fluid out for OEM fluid and friction modifier, and see if that resolves it. It's cheap enough and worth a try, before you tear down.

Diff fluid is the one fluid I don't really mess with as far as 'upgrading'. It is quirky, so I leave good enough alone and stick with the OEM.

Werks

Yep if memory serves me right it was Anthony (formerly with LG) that mentioned in that thread that they used to have to rebuild the stock diff after every or every other race. Bottom line is they wear and honestly I think that most people simply do not think about this and do not know how to check their diff's to see if they are functioning properly. Personally I've been running an OS Gicken LSD in my C6Z which is predominately a track car since 2013 or so with zero issues and it made a noticable difference in handling.

Nowanker

Alas, no.
'Recent' diff fluid did not coincide with the loss of LSD.
No brand of GL5 (nor all the king's horses...) will restore that missing friction.
I'm just surprised that no one else who tracks these regularly has developed the issue.

Nowanker

I was on the OS Giken site this AM... didn't see a listing for the C6Z!
Tempted to explore either that or a Quaife, but then the factory plates and stuff add up to only ~$250...

froggy47

bump and sub

MTPZ06

I was wondering if it was a too much friction modifier added to the mix...because I have seen "too much slip" by doing so. Doesn't sound like your issue though.

x how many more times will your use require this. But yeah, still cheap...just time/downtime involved.

Nowanker

It's a giant PITA, but since I'm not planning to track the car too many more times, I imagine stock plates would last 'forever'. But upgrades are always tempting!
Just heard back from OSG, they say all c5/c6 diff units are the same (?!)
If so, Eaton has something too, and way cheaper through Jegs.

Werks

OS Gicken’s lsd unit, which is an aftermarket part fits in both the C5 & C6 diff housings. In regards to an Eaton diff being available cheaper through Jegs it’s certainly possible. Wavetrack and Quaiff may be cheaper too and stock certainly is but when it comes down to shopping for race parts I have found that “quality” and “cheap” usually do not go hand in hand. Different diffs work in different ways and each has its advantages and disadvantages which you need to research in order to make an educated decision on which unit best fits your specific driving style/handling preferences. It is certainly not a decision that should be based solely off of which is cheaper. If that is your primary concern then you are probably best served just sticking with stock and rebuilding your existing diff.

Nowanker

I like the OSG for sure, seems like all the advantages of a Quaife with none of the downside. Eaton is the same basic functionality as stock, and after looking at all the Wavetrac propaganda, it seems to work much like a stock one too, just accomplished in a slightly different manner.
But the cheap bastard component in me won out... since I'm not planning on tracking this car extensively, the stock items will suffice.
Thanks for the input!

froggy47

For cheap bastards.

Nowanker

If this was my only 'fun' car, I would have gone for the OSG.

Need to finish my real racecar instead of thrashing this one to death...

v8sten

I have rebuilt mine, clutch packs are around $200 from Chevrolet. I used GM gear oil with friction modifier in it. once you rebuild it you will have to do circles in an empty parking lot in both directions to break in the clutches. it was a night and day difference. When I put a clutch in my GS ill rebuild the diff at the same time, while its out.

You can how ever get the LSD out fairly easy in the car. Drain the fluid and remove both axles and diff cover on the pass. side will have to come off. Tricky part is the trans mount. Once off the LSD will come out.