I've got 03 gmc sierra with a 4L60e - 246 - m30 transfer case. It suddenly started making horrible noise in all gears but 3rd. The tone changes as the gears change. Transmission acts as if it shifts fine and not slipping. With truck on rack when wheels turn the noise is definately coming from the last couple inches of the transmission and the 1st several inches of the transfer case. The noise sounds like a grinding noise. Anyone have any clues? It's going to be Monday before it can be checked out at the earliest. No metal flakes in tranny fluid but transfer case looks like it has some stuff in the oil. Any help with this guys?
Just drained transfer case fluid and it's black as West Virginia Coal. I had just changed it about 5-8000 miles ago with the correct bright blue fluid from GM. Sounds like it has let go.
Edited by JAMIEZ71, 03 April 2010 - 10:03 AM.