99 tahoe 4x4 Problem!!!! Please Help

Desperatly need help with my 1999 tahoe. It has the 2HI,4x4 automatic,4HI,4LO option with the press of a button. I recently used my 4HI option for about a day, I switched it back to 2HI when i got home. The next day I started driving the truck normally, after about a mile it started to hesitate,and it got to a point where it would not move if i stepped on the gas pedal, I tried going on reverse and still no answer. Only a zoom could be heard from stepping on the gas. I turned it off and then on, switched it to drive and it worked for about a block. Then it would not move. Had to tow it home. The next day i turned it on, the shifts were working perfect. Decided to drive it around the block a couple of times. The same thing happen. Im thinking that maybe an electrical problem or something else is not letting the 4x4 shifts stay engaged. Any suggestion on what I should do????

Desperatly need help with my 1999 tahoe. It has the 2HI,4x4 automatic,4HI,4LO option with the press of a button. I recently used my 4HI option for about a day, I switched it back to 2HI when i got home. The next day I started driving the truck normally, after about a mile it started to hesitate,and it got to a point where it would not move if i stepped on the gas pedal, I tried going on reverse and still no answer. Only a zoom could be heard from stepping on the gas. I turned it off and then on, switched it to drive and it worked for about a block. Then it would not move. Had to tow it home. The next day i turned it on, the shifts were working perfect. Decided to drive it around the block a couple of times. The same thing happen. Im thinking that maybe an electrical problem or something else is not letting the 4x4 shifts stay engaged. Any suggestion on what I should do????

I own an '02 Tahoe 4x4 but I'm not a tech so what I'm going to suggest is just that, a suggestion.

From past reading, your problem MAY be a faulty switch module.

Pry out the switches in the dash and check for loose wiring connections or other bad solder joints.

Another may be a faulty actuator at the transfer case.

where is the actuator located? is it hard to change

where is the actuator located? is it hard to change


Proper testing before throwing parts at it.

Are you sure the main transmission is not acting up?

What transfer case and transmission does it have?

From your 1st post I suspect you have the NVG 246 t-case (Auto 4WD button). This t-case uses an internal clutch driven by an internal motor to apply torque power to the drive shaft to the front differential.

Since everything was working good before I would suspect a tranny problem.

Need to drain and check the t-case and tranny fluids.

These t-cases need a scan tool that can access the t-case control module. If the t-case is not shifting to the selected position may also cause the trouble you're having.

Hope this helps.

Changing the front differential actuator is not going to help you go forward when in 2WD.

im going to take it to a transmission specialist so they can hook it up to the scanner to see what is wrong with it.

im going to take it to a transmission specialist so they can hook it up to the scanner to see what is wrong with it.


Good idea.
But make sure he is a transfer case trained transmission specialist with a good transfer case transmission capable scanner.
Post back how it goes.