I have an '04 ZR2 that began showing a 4x4 indicator light. I usually would never take my truck to the dealer, but I ended up there. After charging me for the diagnostic, their computer said the encoder motor was bad.

The truck would not stay in the chosen range. I parked it 2hi, but it was in 4lo the following morning. When it did shift back into 2hi, it sounded like the transfer case exploded. I loud banging sound. It did more random switching later in the day. I tried disconnecting and reconnecting the battery, nope!

When I fire it up, the lights in the transfer case switch light up and I can hear the TCCM clicking, but nothing is heard underneath. The truck is now stuck in neutral. When shifting from D to P a grinding sound is heard.

I just replaced the 4wd transfer switch, just to see if the $20 fix would work. nope!

Is what I have described an encoder motor issue or worse?

I have noticed a lot of clean grease below the booty front left. I could not tell if the booty was damaged.

Any help would be GREATLY appreciated.

 

I rarely take my vehicles to someone else, but on the occasions when I've taken it to the Dealer, though you pay more, they've always been spot on for me. Your experiences may be different. It's the "Joe's Autos" type shops that seem to keep throwing parts at your vehicle until something fixes it. So, I think you would end up paying more in the long run. Bottom line, and some may disagree with me, if the OEM mechanics are diagnosing using the OEM tools, standards and equipment...in my experience I would say the Encoder Motor probably needs replacing. But you can look in the DIY part of this forum and there are posts that tell you how to check your encoder. Here's one https://blazerforum.com/forum/tech-a...ill-help-7180/