95 Blazer 4WD issue, not disengaging

[Dave186]

First of all I want to thank oldmaster for his help with the brake issue I had a little while back. Finally narrowed it down to a front caliper.
But heres my next issue (as if I dont have enough). When the 4wd is engaged (it has the floor shifter) it goes or seems to go in fine. But when you disengage it you think its out but after driving a short distance it starts to grind in the right front wheel like the axle is not disengaged or barely touching the hub.
What type of control is inside the differential to engage and disengage the axles? Ive never had one apart and have no clue.
Would I be better off trying to find a good used differential or take that one apart and see what alls wrong?
Thanks again for the previous help.

[old_master]

Under the battery is a vacuum actuator. When vacuum is applied, it pulls a cable that operates a clutch on the right front axle shaft, engaging it with the differential. On the transfer case there is a 3 port vacuum switch. One line comes from engine manifold vacuum. One goes to the actuator under the battery. The 3rd line goes to a vent that usually runs up alongside the transmission dipstick tube with a small filter on the end of the line. If the switch on the transfer case leaks, it will suck transfer case fluid into the lines and actuator. When this happens, the front axle disengages very slowly. If you find that this is the problem, replace all of the vacuum lines, the actuator, and the switch. Then top off the fluid in the transfer case. When in 2WD, you should be able to blow into the line at the actuator with very little resistance, it should come out the filter on the dipstick tube.

[Dave186]

Does it have these even if its a manual shift for the 4wd in the floor? Just curious before I go poking around. I did find a vacuum hose hanging down beside the trans and had no clue where it went to. I will check these out and let ya know. Thanks

[old_master]

Originally Posted by Dave186

Does it have these even if its a manual shift for the 4wd in the floor?

Yes, the only difference between electronic shift transfer case and manual is that the electronic uses an encoder motor on the transfer case to shift it, and a TCCM, (Transfer Case Control Module) that sends the command to the encoder motor. All of the vacuum lines and vacuum switches are basically the same.