I'm planning on changing the fluids in both differential this weekend. (90
k1500 700r4, 5.7l). I am a bit confused as to what to put back in. The gear
oil that I bought at autozone is 80-90 gl5. I am bothered by the small print
on the bottle that says "for limited slip top off only". What kind of fluid
should actually be in this truck? Am I correct in assuming it's the same in
I checked the rpo codes in the glove box. and found GQ1-standard Ratio axle,
G80-limited slip rear diff, GU6-rear ratio 3.42.
I then called the local dealer and he ran the VIN and got the same info. He
advised me it should be a 3.4 limited slip and that I would need an additive
for the GL5 lube.
Thanks for the help,
I don't know. But I've run into a lot of dealership
tech's that aren't aware of this bulletin. I don't think
it will do any real harm to use the additive, as we
used it for years before the bulletin came out. But
now the official policy is that it's not necessary
for the Eaton locking rear diff. It still is used
for the older "limited" slip rear axles.
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