My 98 Blazer with 78,000 miles is stuck in 4 Low. After replacing the TCCM, dash switch, transfer case motor and transfer case switch, it is still not coming out of 4 low. I checked the vacuum actuator under the battery and it is moving when pushing the dash switch. There is no noise or transfer case motor trying to move. I hear the TCCM and the dash switch seems to be working. I'm under the impression that the transfer case motor should work even if the front differential actuator is not. Any help would be greatly appreciated.

 

How did you replace the encoder motor if vehicle is in 4lo? Im really asking. Encoder motors come locked in another position.

 

When I received the encoder, it looked as though it was in the same position as the old one. Is it possible to even mount it in the wrong position? I'm not getting any sound or anything from the encoder motor. Only the click from the TCCM.

 

Encoder motors have a brake inside on a separate circuit from the motor. To move it from position to position, the TCCM energizes the brake circuit to unlock the encoder motor and only then applies the current to move it. If you apply current to move the motor without first releasing the brake (like when people try to run the motor when not mounted on the transfer case to line things up) it can ruin the motor.

Check for voltage across the big red and black wires at the TCCM (EVERYTHING PLUGGED IN) when you attempt to change positions.

 

i removed shift unit from my junk blazer,it was in 2 wheel drive,,,so if i ever need it for my 2001 it should bolt right up??,as long as its also in 2 wheel?...i could swear i changed out one of these years ago WITHOUT removing the drive shaft

 

Please start a new thread if you wish to ask questions.

 

I've tried replacing everything except the actuator under the battery and it's still locked in 4 low. Does anyone know what the procedure is to take it out of 4 low permanently and just have 2 hi?

 

What does the transfer case motor do when you try and shift out of 4wd? Does it make any sounds?

Are you certain that the motor was installed in the correct position for which gear the transfer case was in at the time? (see Les' comment above)

Assuming the new motor was installed in the correct position, it should at least make a noise when it tries to shift positions.

I'll add that the transfer case won't shift out of 4-Low if there is pressure on the drivetrain. I've had a few times where after using 4-Low crawling over rocks and stuff that I have to roll in neutral a few feet on flat ground to relieve the pressure on the drivetrain or it will just flash the light and the motor makes a clicking sound, but won't shift. Another thing you could try is jacking the truck up so the wheels are off the ground to remove any pressure on the transfer case gears so hopefully it will release and shift.

 

The transfer case motor doesn't make any noise, only the tccm click. So it evidently is installed wrong since it's in 4 low. I assume the correct position to install the motor is in the middle position (4 hi) correct ?

 

Which 4x4 system does your truck have? The 3 button or the 4 button? The I believe the 3 button system would be the NV233 transfer case (2wd, 4hi, 4low), and the 4 button is the NV236 which would have auto-4x4. The two are fairly different.

I've never needed to replace the transfer case motor myself, but I've read that if you have the 3 button system, you can probably remove the motor, and adjust the transfer case position manually to 2wd. This tech article may also help if you have the NV233 transfer case.

If you have the 4 button system, check out this thread and maybe it can help you.

Beyond that I think you'll need someone more experienced than I am to help you.