4X4 ENGAGES BUT DOESNT DISENGAGE

[85BURBAN]

any thoughts on why the 4x4 goes on when i pull the lever to 4 hi but wont shut off when i go back to 2 hi the only way i can get the 4x4 to disengage is by unlocking the hubs

[Engineer]

Assuming you have an all original drivetrain in your Suburban, my guess is that you are simply experiencing normal driveline binding that occurs when you engage the 4x4.

I guess my question should be....Are you expecting it to disengage immediately?

The NP208 can, and will have a delay in 4x4 disengagement due to the fact that the linkage is set up so that you can put the transfer case back into 2wd without having to force it like the older NP205, and NP203 required you to do.

Try putting the t-case in 2WD and driving forward in a straight line for a few feet. If your 4x4 doesn't disengage after a little while you may have a weak disengagement spring.

There is a little coil spring on the shift linkage that pushes the 4x4 shift fork into disengagement when you deselect 4x4. If this spring has weakend over time, or the shift fork, and rail have become dirty, or gummed up, this could be the cause of your problems.

Part number 32 in this exploded drawing:

[85BURBAN]

actually the burban was the cause of a idiot blowing a red light and now sits in the driveway slowly being stripped the vechile i have now is a 85 jimmy,and whats happening is the 4x4 goes on works great then when i go back into 2 hi it takes quite a bit of driving i was out in the cemetary today testing it 4x4 worked great on the mud and gravel areas when i got back on the asphalt and shifted to 2 hi it to approxiamately a half mile maybe less to disengage it actually went back in 2 hi when i pulled in the driveway.when its in the driveway i can put the 4x4 on and the driveshaft wont spin,i can shift it back into 2 hi and the driveshaft is free,thanks for the great diagram ill check out the spring like you suggested any other thoughts would be greatly appreciated thanks  again

[joesgarage71]

Have you tried shift trans to netural then 2 hi? either moving or stopped. engine on or off.

[85BURBAN]

no ihavent tried that joesgarage,i tried it while driving then tried it in park but thats what ill try next thanks for the input its much appreciated

[85BURBAN]

engineer, i a little confused is that spring a internal or external part?

[Engineer]

It is an internal part.

To get to it will require disassembly of the t-case. 

[VileZambonie]

You need to check and adjust the linkage first.

[85BURBAN]

oh boy thats not the answer i was looking for engineer,also i did check and adjust the linkage vile i was hoping that was the problem,no such luck,also i failed to mention that when i was playing in the mud a couple of time the shift lever itself had shifted back into 2 hi and it felt like i was in 2 wheel but when i put it back in 4x4 is when i had the problems of itnot disengaging when i hit the asphalt