2000 gmc 4x4 not working

holschuh11 · November 23, 2015

I have a 2000 gmc with the push button 4x4. It wasn't working, but no service 4x4 light and switch lights up like it should. I replaced the front actuator and while I had it on the lift engaged the 4x4 and the front spins, and won't when disengaged. Took it off the lift and tried it out and no pulling from the front tires. Light still works right and can hear it kicking in/out. Any pointers will be greatly appreciated! Thanks.

oldmann · November 23, 2015

I don't know but having your picture sideways is driving me nuts.

sahls01gmc · November 23, 2015

It's possible that there could be a code stored in there somewhere. Takes a pretty high-dollar scanner to find them. Your encoder motor might need to be replaced. The front actuator, encoder motor and dash switch were all known common problems with these trucks.

And yes, your picture looks like you are doing some extreme rock climbing.

00Silverado4x4 · November 23, 2015

It's possible that there could be a code stored in there somewhere. Takes a pretty high-dollar scanner to find them. Your encoder motor might need to be replaced. The front actuator, encoder motor and dash switch were all known common problems with these trucks.

And yes, your picture looks like you are doing some extreme rock climbing.

^^^ That would be my opinion as well.

holschuh11 · November 24, 2015

I fixed my picture haha.

I put my truck in 4hi on my way home tonight just to see what it would do. Now the light is just flashing until I press 2hi again. Does this in 4lo and auto also. Wasn't doing this before, still no service 4x4 light. It did kick into low gear when I put it in 4lo but still kept flashing and no power to front wheels. Still think it's the encoder motor?

Thanks in advance!

sahls01gmc · November 24, 2015

"Could be". I'd try to get it scanned first just to make sure so that you don't waste unnecessary money. Unless you have that, which in that case send me some....

holschuh11 · November 25, 2015

Haha alright thanks. Nope don't have any extra change to share. Wish I did lol. Old girl has 248k miles.

holschuh11 · December 15, 2015

Just had my truck on the lift, the front tires turn in 4x4 until you hold the front tires. Are there clutch packs in the transfer case? I checked the fluid in the transfer case and it was black and stunk bad. Front actuator and transfer case motor both sound like they're working properly and no service 4x4 light still.

Thanks in advance!

00Silverado4x4 · December 15, 2015

No clutches that I know of in the transfer case. It uses a shift fork and a chain. If your fluid was black and smelled bad, it may be time for a rebuild/replacement.

holschuh11 · December 16, 2015

Damn, I was afraid of that. Thanks for the help!

holschuh11 · December 17, 2015

Also i forgot to mention my ABS light is on. Would that cause an issue with the 4x4?

00Silverado4x4 · December 17, 2015

I don't think so, ABS light could be the sensors on your front hub could be bad or corroded. Your best bet with the ABS light would be to get it scanned to see what it says.

sahls01gmc · December 17, 2015

The ABS light could be from the ABS module mounted on the driver's side frame rail. The ground gets bad on those, and sometimes the module itself needs to be re-soldered...there's a thread on that, I'll post the link if I can find it.

Sounds like the transfer case needs some internal work. Keep us posted on the progress!

holschuh11 · December 21, 2015

Ok, thanks for the help guys!

holschuh11 · February 4, 2016

I put in a used transfer case and 4x4 worked. Making a heck of a noise in the front on tires are squealing and jerks back and forth. But today I was in 2x4 and attempted to go in 4 hi while sitting still and it didn't work. Drove on home and tried again while going up my driveway and it went in 4hi. But now it won't go out. Won't go to 4 lo or back the 2x4. Only 4 hi and auto 4x4. Can hear front actuator and encoder motor mouth working. Sounds like they shift and then shift back then do it again. Then I get the service 4x4 light. Anyone have any idea what it may be??