Want to change out my rear end gear oil, so I picked up some Valvoline synthetic 75-90 and a bottle of additive for the limited slip. Upon reading the label on the back of the bottle, it states that it is not recommended for limited slip rear ends at this time, the gear oil. Will the addition of the additive for the limited slip, make it usable. Thanks

Joe

 

I use "Redline" synthetic oil in my 8.8LS rear. I had a long conversation with Redline's tech guy who told me it was perfectly permissable to mix Ford's LS additive with Redline's regular lube, or, simpler, to just buy their product made for LS rearends.
Since I already had Ford's friction modifier, I mixed my own. After more than a year in the axle the factory limited slip works just fine.
My advice would be to call the manufacturer of the oil and talk to their tech guy.
Eddie