When pulling 5th wheel a straight pull sounds OK. When turning from a stop it sounds like rear end noise. When not loaded noise is not there. 93K miles

 

do you have limited slip or a locker in it???


might just be the clutch spinning around. have you checked the fluid? is it clean?

 

how do I know difference between limited slip and locker? will go out now and check fluid

 

When I got the plug out there was a very thick gunk on the inside of plug. Oil did not run out of the hole and my finger brought out oil about the consistency and color of maple syrup. probing deeper with my finger got quite dirty with a dark grey thick gunk

 

What kind of a noise is it making? Clunking, chattering, growling, etc?

 

chattering I have found many web sites about changing diff fluid. It does not seem to difficult and I am going to do it. I will also be using the additive from FOMOCO unless anybody thionks differently. Looks like REDLINE is another good gear lube.

 

Sounds like a good place to start. Drive the truck a bit to get the lube warmed up and mixed prior to dranining.