Got a 99 Blazer 4 button Auto-Trac 236GM with fluid leaking out bottom of encoder motor. Looks like its coming out around the rubber grommet where the wires go in. Had to add about 3/4 of a quart of fluid to the transfer case. It's been leaking for quite a while and this was the first time I added any fluid to it. The encoder motor was replaced at a dealer about 3 years ago. Still working ok. What I am trying to find out before I take it off is what keeps the fluid out of the encoder? Parts diagram I looked at doesn't show a regular oil seal on the shifter shaft. Does the insulator that goes behind it seal it or does it even have the insulator? Or is there a o-ring back there? Just trying to scope it out a little before I tie into it. When it went out 3 years ago it was in the middle of winter and I was working so I just let the dealer fix it. The only part that was on the ticket was the encoder. No gaskets, seals or anything else. Any help would be appreciated. I was a mechanic years ago and did industrial maintenance for 30 years so I am not a complete novice but if I am not comfortable doing something or don't have all the tools I need, I know when to leave it to the pros at the dealer. Thanks for any info.

 

Did a little more digging on the internet. Looks like maybe the encoder shift shaft bearing might have a seal built into it. If its bad I think I'm in trouble. I don't see how you could change it out without a complete removal and tear down of transfer case. Anyone know about how this is made and how to replace?