OMG! Check your diff fluid levels!

So I decided it was time to put new differential fluid into my 2wd silverado 5.3. I bought some 75/90 synthetic valvoline gear oil, and a fel-pro gasket. There was no real sign of leakage, maybe a tad "darkening" around the edge of the diff cover, nothing major

Drained the fluid, cleaned cover, and diff real good with non-chlorinated brake-kleen. Checked the capacity with NAPA and I am supposed to have 2.1 quarts.

When I was done, I drained the old stuff back into the jugs, and I only filled ONE jug! And the old gear oil had a can of brake-kleen, so I am guessing there was less than a quart.

My Point: CHECK YOUR DIFFERENTIAL FLUID LEVELS:runaround: !

I would recomend checking all fluids everytime you change your oil.

Yeah I usually do. Except the gear oil, I assume does not get "used". I wonder where an entire quart went? I think it was underfilled by someone who did not know how to convert pints to quarts.

If you have full floating axles like the 3500 after refilling the rear differential its a good idea to jack up one side first wait awhile like 20 minutes and check level, repeat for other side. This fills up the axle hub housings at the wheels with fresh oil, otherwise you risk running on dry bearings and may burn up the axle seal, on my 2002 3500 its no easy affair replacing them, some older 3/4 ton trucks had full floaters as well, that where you can remove the actual axle shaft.

is 75/90 synthetic gear oil the recommended lube for that truck? I've got a 99 Silvi which needs some fluid, but the truck did not come with an owner's manual, so I wasn't sure what to put in.

Most oil change places do not do this,check differantal,manual transmissions and transfer cases.I have seen one Dodge Durango with burned up carrier bearings and gear in the rear end due to the dealership not checking it during an oil change.It had a cup of fluid in the differantal and there was about a $600.00 repair bill.