It's sensor may be on the trans, axle, or wheel ends. Regardless, the processing by the computer is the important factor.

Thanks , i'm going to see about changing the fluid , i looked late this evening and it is dirty , so i will attempt this week to flush out and check the adjustment on the drums ..

Eric

Not to be a smarta$$, but on my 1996 i did all that ( more then once ) and even changed the load valve or how ever u call it .
Nothing helped ..the rear drumms on the GMC/CHEVYS suck thats just fact.
Thats why i am going to do this conversion and a buddy is working for GMC he said i dont need to change anything else, the ABS will be fine !

Both Ford and GM market good quality HD brake fluids that are a safe bet. Happy flushing!

The problem on that generation of trucks is not the rear brakes, its the front brakes. They are working too hard, but its because the pads are way too small as are the calipers.

The rear brakes were the largest diameter drum on any of the big three 3/4-1ton trucks. The front rotors are close in size to the others but GM used a small 1 piston caliper with very small brake pads.

There used to be a company that made a kit to use Ford 1ton calipers and pads on the front of Chevy/GMC trucks 88-99/00

It is a good kit because you are still using parts that are avail anywhere, not custom stuff you need to order like Willwood or something else aftermarket if you ever need parts in the middle of nowhere or on a weekend.

No sure of the name of the company right now, but you could probably find it with a google search.