I recently changed my rear diff lube on my H9 (3.55 LS) and used a quality synthetic with limited slip additive. Recently I noticed a slight chatter in the rear during tight turns on warm asphalt or other good traction surfaces. I suspect that there was not enough LS additive in the factory lube or maybe this is normal? I don't want to add more additive and mess up the LS properties but is this bad for the diff and I should add it anyway?

 

Add a bottle of L\S additive.

 

Use FORD additive, go to the dealer to get it.