Rear diff 8.25 LSD making noise

[N5506J]

99 Cherokee UpCountry
4.0, auto, 4wd, all stock, 94k

The rear diff makes noise when backing up in a turn, not going forward! Kind of a pop, pop sound. Fluid was recently changed, Mobile1 85-140. I assume it is the clutch plates, is this normal. The diff is tight when you try to turn one wheel?

 

[Flyfisher]

did you add the LSD friction modifier with the fluid change?

 

[CompleteCherokee]

^^^ this

 

[MAY POP]

Parts stores sell small containers of friction modifier for LSDs. under 10 bucks.

 

[sw4218]

My 93 did the same thing till I added the LSD friction modifier to the rear diff

 

[CompleteCherokee]

did you do this? If so, did it fix the issue?

 

[tjmotter]

I had a lube place replace the fluid in my LSD and they swore that the new lube had friction modifier in it. It didn't and I had popping noises and groaning coming from the rear end too. Local Chrysler dealer added a small bottle of friction modifier and the backend sounded normal again.

 

[Tony_SS]

Synthetic fluid does not need the friction modifier, correct?

 

[CompleteCherokee]

I've always added it regardless of fluid type

 

[md21722]

Mobil and Redline sell both "LS" and non-"LS" formulations, one for limited slip and one without.