What is the correct part # for GM's diff fluid?
 

I have a 98Z28 6spd. The part # listed in our parts thread and has been replaced according to SDPC, but the replacment is 22 dollars :confused: I've think I've gone thru about 5 parts #'s for GM's rear diff fluid on SDPC. They do list the GL4 fluid but that is the older fluid. Can anyone help!? :(