I have a 1993 gmc k3500 4X4 the rear end is a little low, my manuel says the back one uses 80 90 gear oil and the front one uses 80 90 GL 5, all I can find here is the GL 5 can I use this in this rear end. Thanks

 

ive never been into a front diff on a chevy ifs but ive been into my 8.5 in the half ton and the 14 bolt in my 2500 the 8.5 is a limited slip so it gets special gear lube with a friction modifier I couldn't tell you what I put in it its been a while but the 14 bolt is just an open rear end so it does not need the friction modifiers all its got to lube is the ring pinion and all the bearings..... so it gets the same stuff I put in big trucks at work. its usually cheaper than that limited slip special stuff to. Its just 80w 90 hypoid gear oil