About a month or so ago, I replaced my transfer case. For a while, it was fine. AWD was working great, no crow hop, no binding, all that good stuff.

Just recently, the service AWD light came on. When I turn the key on, I hear a clicking coming from the passenger's kick panel and the AWD light stays on. The clicking stops after a couple of seconds. I just went and tried it out on a nearby dirt road, and I think the AWD is working in and out. When I put it to the floor, I feel the rear wheels slipping and acting like traction control is coming on like in my Alero. It jumps. It's like slip, grab, slip, grab. What could be the culprit? I'm hoping just corrosion on the tccm.

99 Olds Bravada NP136

 

The best, easiest way without throwing parts at it would be to get someone that has the proper tool to read the AWD codes. I know I ran threw my own NP136 woes and it turned out to be the encoder motor, but it could be a number of things.

The code reader will tell you what it is most likely. There is no cost in checking for TCCM corrosion and ensuring you have no wires loose it broken, but beyond that you'll be throwing money at it.

Something else that was recommended to me was to ensure the fluid was fresh with autotrack II fluid, which you can get at the dealer or on Amazon as I have found.

 

When the t case was changed, I put fresh autotrak 2 fluid in it from the dealer.

 

I'd recommend finding someone with a scanner capable of reading the NP136 codes. I suspect it's either the transfer case clutches (as you said slip, grab, slip, grab), or the encoder motor itself, but this is just my opinion. You can't go wrong checking for corrosion in the TCCM connectors or plugs around the encoder motor.

 

The tccm only clicks when the key is turned on, before starting. Would the tccm still click like that if it was a mechanical problem?

 

No idea, I'll check what mine does when I leave work today and let you know.......

 

Mine clicks when I turn the key also, so sounds like a relay click for power to the encoder motor. Again makes sense to get the codes read but I'd bet it's your encoder motor.

 

That's what I'm hoping. Mine clicks like 4 times, the service AWD light stays on. I'll pull it and clean it this week.