03 rear diff fluid question

[blacklx]

Hello, having the rear diff fluid changed in my 03 Tahoe today. Can anyone clear up what fluid and if it requires friction modifier?? I purchased the GM 75w90 fluid but they couldnt tell me if it needed the friction modifier. It is a limited slip diff. Please advise asap. Thanks in advance.

 

[dsump]

If you have a limited slip then you need the friction modifier.

 

[blacklx]

Thanks for the info. Just wasnt sure. Been a Ford guy for years. Didnt want to assume anything.