what fluid does my rearend take? 2001

I have an 2001 Isuzu Rodeo and need to change the rearend fluid.

Rodeo is a 2WD 3.2 liter. Automatic. 150k

I bought some positrak additive but autozone could not tell me what fluid to use.

Any help would be greatly appreciated.

Thanks

You only need the additive if you have a Limited Slip Diff.

:):)For the 04 the book says SAE 90W or 80-90W for 0-90 degrees and for consisttently above 50 degrees use 140w. Im sure yours would be the same.:):) Andie