low speed clunk in rear end

[SVO]

One other item to check is to see if the spring perch on the rear cover is broken.

 

[GTR1999]

Yes I agree change out the diff oil. I use Lucas 85-140 and 2 bottles of GM additive in my builds. You can use 90 wt gear oil if you like. You most likely are not going to break anything, this is an inherent problem with the spring pack/clutch posi design.

Stock posi's are setup on the production line and the spider lash is 001-008" Too tight, add in the spring pack and the inner wheels will chatter on a corner when hot. The additive is not the same as it once was, that is why I use 2 bottles where I used just 1 before. That is with a tuned posi not a stock type.

 

[Tom Bryant]

Back in the 70's when I was in GM parts it was whale sperm oil. I don't know what it is now. Whales don't cooperate like they used too, I guess.

Tom

 

[SVO]

Uh, Tom, I believe that is suppose to be sperm whale oil. otfl

 

[GTR1999]

I noticed when the packaging and part number changed a couple of years ago 2 bottles were required.

 

[Tom Bryant]

Uh, Tom, I believe that is suppose to be sperm whale oil. otfl

I must have been holding the bottle upside down.

 

[toobroketoretire]

I was having a horrible BANG BANG BANG coming from my rear end and after a lot of troubleshooting I discovered the horrendous BANGING was coming from my the inside of my TH700R4. The front planetary had spit a thrust washer out and it was the broken pieces of that washer getting pulverized that was causing all the noise. While I had it apart I changed over to the newer 5-pinion planetaries and that solved the problem.

The point I'm making is a problem in the transmission can cause a shock down the driveshaft and into the rear end so keep that in mind.