hum or howl in 4wd

[DaveO9]

I used my 4wd for the first time in a while during a snowstorm a few weeks ago, and these symptoms don't give me the warm and fuzzies after reading this.

In 4wd hi or auto - slight growling low vibration under acceleration, stops when foot is off the gas.
Goes away completely in 2wd.

Crap.

Yeah, sounds pretty familiar. I just took my carrier out tonight and tomorrow will put in the replacement unit from LKQ. I split the two halves and looked inside, but haven't seen anything crazy obvious yet. I'll do some more checking tomorrow and report back.

Guys - I'm thinking since I have the diff out a second time, I'll go ahead and do the oil pickup tube o-ring. My oil pressure seems to be getting worse. It's just over 20 psi at highway cruise RPM now. Seems pretty low. I bought a Fel-pro oil pan gasket and o-ring today, so I think I'm ready. How hard is it to drop the oil pan? I know you have to get the timing cover off to get to the actual pump, but it looks like you DON'T have to do that if you're just replacing the o-ring? I know you do have to lower the steering rack to get the pan off, but that doesn't seem too crazy....

If anyone has any thoughts or advice for this one, please let me know.

 

[TrybalRage]

You should not have to remove the timing cover, no.

I put a junkyard 5.3 in my C10, and I replaced the pickup o-ring on that before I put it in the truck - I never took off the timing cover. That was a gen3 motor but I don't think it should be different.

I have no idea how hard it would be to get the pan off with the motor still in.