differential oil

[Sparky]

What's the consensus oil for CS differentials? Is the same oil still recommended for both LS and non-LS diffs. Has anyone had any bad experiences with Red Line 75w90 GL-5 or Mobil 1 LS 75-90 or is another oil preferable.

Thanks.

 

[deQuincey]

again it will probably not be a consensus, but for notLS sae 90 is the rule

 

[Sparky]

I'm not sure if it is a LS or not. I was told by the previous owner that it was a LS but the case markings don't appear to indicate that so I wonder if the carrier has been changed (if that is possible). I thought I would run the correct oil for the LS just in case. I would prefer to use a synthetic.

 

[Honolulu]

Easy enough through several methods to find out whether you have a LS diff, and it has been discussed here before. Simplest raise both rear wheels, transfer in neutral and handbrake off. Rotate one rear wheel by hand. If the other wheel turns the same direction you have a LS diff. If the other wheel rotates in the opposite direction, your diff is not LS.

When I changed my LS diff oil and used "regular" diff oil, it would "groan" during low sped tight turns. A small bottle of GM diff oil (about 4oz) removed the groan.