Chevy and GMC Duramax Diesel Forum banner
1 - 1 of 3 Posts

· Registered
377 Posts
If the metal chunk is a thin shiny piece of hardened steel, it's probably the piece that's suppose to prevent "pump rub". If you haven't read about pump rub, you should since it's common and probably inevitable in our magnesium transfer case housings. The hardened steel clip prevents the pump ears from eating a hole in the tail section. But they tend to come loose after awhile.

The pump rub hole presents as a tiny pinhole and the ATF leaks out so slowly it doesn't leave a puddle. That might be why it was a quart low (half of the ATF was gone). It's probably gray because it's never been changed before.

I think GM has a band-aid fix, but 3rd parties have better solutions. Search for "pump rub". You might already have a pinhole, so you probably need a new tail section (they also make aluminum ones, which should hold up better). If the t-case still works ok, and since it didn't go dry, just run with it.
1 - 1 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.