bump bump

 

as kyle just mentioned
"The posi-lock setup only deals with the front axle, not the transfer case"



posi lock setup being some sort of setup to lock the cable in the pulled position.....

 

1986 s10 2.8l v6 4x4 had the same problem.

Ive had the same with my four wheel drive engaging and not engaging and ive searched the forums just like you and couldn't find a thing. i have a big feeling it is your transfercase switch... on the transfercase on the drives side you will see three vac lines going to it. one for breather/vaccum/4x4. you can purchase this part at your local auto parts store and i believe it is a 7/8 wrench i had no problem jacking that side of the car up and reaching my hand up in there as it is pretty tight. ive managed to get the wrench up there as well. this should take you a good fifteen minute job. make sure the threads on the switch are good and when the hoses can only go on one way. there is a hole between two hoses in order to slide it on the guide on the tcase switch. i hope this helps let me know