4x4 works sometimes. shifts transmission into nuetral by itself.

SOURCE: 1994 chevy s10 blazer 4x4 push button type

small sylinoid on the top of the transfer case needs replaced. easy to do. it has three vacumelines going to it just trun out and replace like a bolt.

SOURCE: 4x4 not working when i shift it in 4x4 auto trans

Find the accuator on the front axle it has a two wire pigtail and threads into the axle housing. Check for power and ground if you have both when the transfer case is in 4x4 the replace the accuator. They are available at most parts stores and are a very common problem. Let me know how it goes.

SOURCE: 95 tahoe four wheel drive stopped working/shift light not working

I have a 1996 tahoe that did the same thing to me.

There is no vacuum lines, it is all electric. The motor on the front differental is controled by the actuator switch on the top of the trans case. The motor is controled by 3 wires. 1 is a ground and the other 2 are signal wires. When the truck is in 2wd, the motor will get 12volts to ground on 1 wire all the time to turn the motor out. When you put it in 4wd, the motor will get 12 volts to ground on both signal wire to turn the motor in.

Here is the point!! Check to make sure that none of those wires from the t-case switch to the motor are shorting out on something metal. In my case those wires came out of the wire loom(black tube) and rubed the insulation off. shorting on the t-case.

If your truck ever gets stuck in 4wd, were you have to keep it in 4wd or the front end makes a hell of a noise, the actuator switch on the t-case is none to go out. cheap fix. If that ever happens and you are in a pinch. Unscrew the motor out of the front end and manualy give the motor the signals that it needs with jumper wires and the trucks battery to turn the motor out, screw the motor back in. Don't put the wires back on till you can fix it right.

SOURCE: po 751 code 99 tahoe

The solenoids are located in the transmission. There is one for the 1-2 shift point, one for the 2-3 shift point, and one for the 3-4 shift point. You have to drop the transmission pan to access them.

SOURCE: transfercase control module

I fould my yhis morning. I have 1997 GMC Suburban the Transfercase Module on my is Driver Side under Dash Left of Steering Column. Rectangle Silver box approx.5" long white connections. Good luck getting to it took me quite a while. There are 2 Screws on bottom of Module and 1 tab on top that is difficult to unhook. Where is the Shift Motor on Transfercase.