That's the plan....once the shop gets it apart, they will let me know what I need....the bearings were new when the rearend was built....there are maybe 4000 miles on the bearings (all of them race miles).

I did just change the ring and pinion to 4.77s....I trust the shop that did the work....I don't know what they could have done to the bearings to make them wear out that quickly after the R&P swap.

 

Fried LSD? Tastes like chicken.

 

Hmmmm.


interesting

 

Actually, I'm surprised that most people DON'T have failures within 4k miles of their r/p swaps. Most shops are grossly under-qualified to be doing rear end rebuilds.

Setting up a rear end is not like insatlling shocks or changing a clutch. When you set up the rear end, you need to accurately measure and set your backlash, preload, and contact patch. I hear people talking about how their mechanic did their gear swap in 4 hours. I don't think anyone could do properly in 4 hours unless this is the only job they do all day long and they have all the pieces lined up and ready to go. Doing it right takes proper measurement devices (dial gauge, push/pull gauge, and some prussian blue) and lots of time. You generally have to put everything together, check all your variables, then press it all back apart and change the shim at least once or twice before you get it right.

Do it wrong and you cook the bearings and get a failure.

 

An incorrect build can cook the carrier bearings?

I was planning on having the shop that did the R&P swap do the full rebuild. How can I tell if this was a put together wrong? If they did it wrong the first time, I don't want to have them do the full rebuild.

 

Yes, an incorrect build WILL cook the carrier bearings. They are tapered roller bearings and have to be properly preloaded. Too much preload will generate excessive drag/friction/heat and wear out the bearings. Too little and you get play and shit starts moving around and getting cooked.

To put it simply, if it's cooked in 4k miles (and you're not drag racing with a turbo on slicks), they did it wrong - end of story. There's no reason why a road race car (I'm assuming you're on R-compounds) should blow a diff that fast.

 

hey pete... it is a haul, but you may want to talk to Jeff at Ganley... i ended up trailering my car the entire way out there just to get the R&P put in last spring. They had done about 30 of them at that point so I trusted them much more than the local mustang guy.

I guess you could send your whole rearend (to the car) out to save some time and gas $.

Goodluck.

I have the stock lsd...plus I have no idea how things work so I can't help with anything else.

 

Well, actually....it was only weekend. The R&P was swapped and then I ran the enduro at VIR. It was making noise early in the weekend, so it seems it was having issues right from the get-go. Since I trust the shop so much, I thought it was just a coincidence and that the LSD was going bad.....

 

I am going to have the rear evaluated and if it was assembled incorrectly, I am going to have somebody else do it. Scot - please don't mention any shop names since I don't want anybody to get thrown under the bus...even if they did do it wrong.

 

Just an update - I had the differential checked last night (by another shop). They first checked all of the specs on it and said it was 100% correct. They then disassembled it and went to work on the LSD. They said that the LSD is fried - the clutches are worn out. I guess the worn clutches would explain the heat. So, I spend the money on KAAZ fluid and my LSD wears out and other folks don't run the KAAZ fluid and get 60K miles out of theirs....go figure

If the fluid wasn't the cause of it wearing out, I don't know what is...I broke it in myself by the directions...not sure what else it could be.

I'm just glad to know the shop I used does good work and will be able to build my new one properly.

Thanks for all of the info on this - I appreciate it.