I can here the axels engaging when I push 4L on the dash. With all 4 tires off the ground the wheels spin as soon as you grab them they stop. Popping out of 4 wheel mode. Just had all the vacuum leaks fixed and know the shop says I need a new transfer case. 1999 s10 blazer 4 button on the dash. Thank-you in advance

 

it might be your encoder motor

 

put the truck in nuetral, shift into 4l, put the trauck in park.
reach under the truck and try to turn the front driveshaft. If it turns your transfer case is not in 4x4 mode. does the dash light blink?


putting the truck in the air to test 4x4 is ok, and yes the tire will stop if you have open differentials.

 

The encoder motor? How would that kick it out? The lights on the switches blick when pressed then remain solid for the button pushed. Hear it clucking in and a clicking right side. Just won't stay locked in

 

Have you verified that the front axle is locking in? There is an engagement vacuum actuator under the battery that needs to work for fully working 4wd.

 

Yes the front axels lock in but pop right back out under ANY load

 

Seems to be the encoder motor. How do I know which to get? NP?

 

i got the stock one but in ur case u might want to go aftermarket unless u have the money to afford the gm one.