Transfer case stuck in 4-low

[Drec]

Is there an easy way to shift this back? I was backing a trailer into my driveway and selected 4-low to eliminate the wheel spinning in the gravel, then it wouldn't shift back out. Do I have to troubleshoot the whole system to fix this or what?

I saw another similar thread, https://gmtnation.com/forums/threads/stuck-in-4hi-but-not.17915/. This Envoy seems to be failing me when I need it most. We are just in the starting faze of moving, so working on a car now isn't the best timing.

It a 2001 Envoy.

 

[Mooseman]

Getting it in and out of 4lo is a little more tricky. You have to move the truck a little very slowly. If it absolutely refuses, maybe the encoder motor died in that position. You might have to pull the encoder motor and try to shift it manually with pliers or something.

 

[Drec]

So should I be driving it slowly and try to shift it then? The lights on the selector blink and seem to be working.

If this doesn't work, where is the best place to get an encoder?

 

[Drec]

If you unbolted the encoder and then tried to operate the switch, in theory, the motor should turn, right? Then if it didn't you would know that, could be the problem. Is that the only way to test it without bench testing it?
If the motor did run, could it just be weak and not be able to overcome any load in the system.

 

[Drec]

I found this interesting post after a Google search, on a transfer case encoder diagnosis:

http://forums.offroadtb.com/viewtopic.php?f=26&t=3952#p68953

 

[cornchip]

I use 4WD low frequently to back trailers up a hill behind my house. I'd recommend to anybody when shifting into any 4WD range from 2WD to be on a very slight grade and have the transmission in neutral. Letting it roll forward with out power is the key.

 

[Mooseman]

So should I be driving it slowly and try to shift it then? The lights on the selector blink and seem to be working.

If this doesn't work, where is the best place to get an encoder?

RA and Amazon are the usual places. I think most are rebuilts so there is a core charge.

If you unbolted the encoder and then tried to operate the switch, in theory, the motor should turn, right? Then if it didn't you would know that, could be the problem. Is that the only way to test it without bench testing it?
If the motor did run, could it just be weak and not be able to overcome any load in the system.

Yes, you should be able to test it this way as there is nothing in the TC that reports back to the TC module regarding engagement. It's all in the EM.

 

[Drec]

So after trying everything that was suggesting, I gave up last night, with no results. I went out a few minutes ago to drive it up on some ramps, and it was in 2-high. Took it out for a short drive and it isn't in 4-wheel drive now.

So the question now is, will the only way it would shift into 4-wheel drive, be if I shifted it? After I get moved, I could delve into this and figure what is happening.

I suppose, if I wasn't shifting it correctly, and something I tried last night was all the magic that it needed to get it back into 2-wheel drive.

 

[Mooseman]

Shifting in and out of 4lo can be a bit tricky. It may have just been a procedural issue.

 

[Nexus1155]

Not trying to be "that person" but I had a brain fart moment before when shifting it in an out of 4lo... do you have the vehicle in neutral with foot on brake? Not park or drive. Correct?

 

[Drec]

I’ve shifted mine in and out before without any problems. When this issue popped up, I had shifted it into 4-low, backed the trailer in and parked it, without shifting back into 2-hi. Then the next day my wife needed to drive it and called me because it wasn’t driving right and I told her to shift it back into 2-hiwhich she wasn’t able to do. So whatever she did didn’t work.