Bravada AWD Issue
 

I am literally about done with this, I hope someone can give me some insight....

Last winter I had AWD issues, and after some work we replaced the encoder motor and got the AWD working again. Currently no codes and the ABS works fine. Yesterday we got hammered with snow and my AWD did fine until I tried to go up an unplowed hill and then lost my AWD. No servivce AWD light, just all of a sudden lost my front wheels pulling.

I pulled over, check the 4WD fuse in the fuse box was fine, but the ATC fuse in the engine compartment was blown. Replaced it, restarted, and got my AWD back. Today went out to the store, AWD was fine, got home, got caught in some deeper snow in the front of the house, lost AWD again. Fuse in the engine compartment blown again. Replaced, got AWD again.

The encoder motor was a new one from Advance last year....has a warranty, and I replaced the transfer case fluid last winter with AutoTrac II.

I wasn't hot rodding it in the snow, but it was deep snow. Any ideas here? Are the Advance Auto Parts encoders cheap like that? Do I need an AC Delco one? Or is there someone that has seen something like this before, such as the prequel to a transfer case issue?

Any ideas here? After all this I am SO missing just locking hubs and a transfer case shifter in the vehicle :(

Your transfer case is a single speed case. If or when the TCCM detects the rear wheels losing traction, the encoder gradually actuates the clutch pack in the transfer case so it applies more power to the front axle. If the encoder, linkage, or clutch pack binds, electrical resistance increases, and the fuse will blow. The ATC fuse feeds the encoder motor.

So it would be any of those systems....would there be a relatively easy way (in warmer weather) to determine which system is the one encountering the issues?

Without a scan tool capable of commanding the encoder motor, you can only guess;) You can remove the encoder and try moving the shaft manually with a suitable wrench. There will be some normal resistance, but if you really have to yank on it, there's a problem in the case. Try that, or try another encoder motor. DO NOT operate the encoder unless it's mounted to the transfer case. There are no "stops" in the encoder and it will destroy itself. The case and encoder MUST be aligned correctly before installing the encoder, (instructions that come with the encoder explain).

I've got 268k on this thing, could a transfer case that's wearing out work fine in light conditions but cause the above situation when under major load? Obviously I know it could me other things buy just trying to figure worst case cost.....

Also, last question and I'll leave this alone...are the AC Delco encoders that much better than the Advance Auto brand (Dorman, I think)? I know these trucks love ACDelco on most things, didn't know if anyone had run across this question....

The same thing happens under all conditions, load doesn't matter. I've installed Dorman encoders with no problems.

Just decided to take it to the transmission shop to look at. This guy is a family friend so I feel good that he won't screw us. I'll let you all know I find.