I got my truck back from my cousin, he replaced the head gaskets.

It now will not disengage from 4wd. I have the shifter in 2high and its running in 4high. I can even switch it to 4 low, but wont disengage the front shaft. I even tried unplugging the 2 vacuum hoses and it still wont let go.

does anyone have some insight for me on this one?

greatly appreciated, il be outside scratching my head starring at the truck.

 

Do you have an auto or manual trans? Add or locking hubs?

 

If you have "the 2 vacuum hoses," I'm guessing ADD. The ADD is driven by vacuum in each direction, so disconnecting the two hoses just leaves it where it was (in your case, engaged). http://personal.utulsa.edu/~nathan-b...26addcontr.pdf

But since it is not coming out of 4wd with the transfer case shifted to 2high, it's probably not in the differential. In 2high the transfer case disconnects the front drive shaft. Even if the front differential remains engaged, it will just free-spin the front drive shaft.

My guess is the linkage got bent/bumped/mis-adjusted. Climb under and watch the linkage while someone shifts it for you.

 

isnt the linkage internal? anyway, we will need more info on your problem. is your t-case stuck or just your front axle ?

 

On a manual transmission the transfer case is. But if he has an auto the linkage for the t-case is external.
Agreed we need more info on your problem.

 

Hey thanks so much for all of your time!

My fault, I left out that its a 5 speed.

I was told that if I cant spin the front shaft by hand im in 4wd. Than if I read this right, some 4wd front shafts always spin, which would make me think I wouldn't be able to spin the shaft at all.

 

Not to try and point out the obvious... but these trucks are known not to want to shift out of 4wd on paved surfaces. Try shifting out on low-traction ground (dirt, gravel) or rock it back and forth in reverse and first gear a bit. Mine will usually shift out, but if I wait until I'm on paved road it gives me grief.

 

Is that how you "know" it's stuck in 4wd? (Put another way: on dry pavement, if you try to turn a corner do you get front tires squealing? If not, I'm not sure it really is in 4wd)

While sitting there in 2wd, the front shaft should be disconnected at the back (via the transfer case) AND at the front (via the ADD, assuming you have ADD, which you probably do if you have 2 vacuum lines). If ONE of those is not disconnecting, you can't turn the front drive shaft by hand, even though it's not in 4wd (because the other end IS disconnected).

 

sorry for the lack of info again. im bad with any digital form of communicating, I hate texting and all that junk.

I know for sure its in 4wd, I have also takin the truck to a dirt road to be sure, I can switch from 4 high to 4 low no prob, but wont disengage to 2high.

the truck had no problems getting in and out of 4wheel before my cousin redid the heads.

 

did you try to back up, and the try to put it in 2high? My old '84 sometimes wouldn't come out of 4low til I did backed up a few feet.....

 

yea I did but maybe il try to go from 4low straight to 2high after a bit of reversing.

Im thinking about just removing the front shaft temporarily until I can drive it back to my cousin for a fix.

What do you think about that?

 

this is a common problem. try to go back n forth about 20 feet in strait line. most of the time it works for me. if that didn't work, check the oil in transfer case.

 

If you think the drive line is bound up, it's pretty easy to free it up by jacking up one front wheel. That'll relieve all stress and it should come out of gear. If not, rotate the lifted front wheel forward and backwards vigorously to try to break it loose. Just keep hands and feet out from under the tire.

 

alright! more great advice. I will do that tonight when my buddy gets home. my driveway is damn near vertical, great for burping a cooling system and that's about it!

I will let you all know how it goes.

 

No luck.
I had the front end up on jack stands and it would let go.

I went back to the dirt road and went back and forth forever and no luck again.

I keep refining my search to find any hope, and cant find anything.

Is it strictly a mechanical issue? would a cracked vacuum line hold it back? or maybe a solenoid?

Anymore help would be greatly appreciated, I have no choice but to drive it in 4high to work and school, im just taking it easy and watching for sharp turns.

 

I'm going to assume you meant "I had the front end up on jack stands and it wouldn't let go." Otherwise the rest of your post is pretty confusing.

Does the green 4WD light stay on? If it has ADD, try jacking up the front, swap the vacuum hoses at the front differential, then start the truck. If the green 4WD light goes out, the ADD has released and it is safe to drive on the pavement. Leave the hoses that way and don't mess with the shifter while driving, until you get time to dive in deeper.

Alternatively, you can just pull the front drive shaft until you get it figured out. It's only 8 bolts, 4 on each end. That'll keep you from breaking anything on sharp turns.

Longer term it sounds like you're going to have to get into the transfer case and figure out what is jammed. I'd start by pulling the shifter lever off the top from inside the cab and examining the linkages.

 

some simple info. for 4wd the t-case AND axle must be engaged
front axle engages via manually operated locking hubs OR by ADD
ADD operates via two vacuum lines that moves a gear within the axle
manual hubs operate by hand at each hub
w/ ADD the lite is turned on by switch in the axle housing
w/manual hubs the lite is turned on by t-case
the shifter operates the t-case via two actuator shafts inside
with shifter held to the left it operates 2wd and 4wd shaft
when held to the right it operates the hi/lo shaft
they shafts work independently and are not connected
with this said its easy to see our need for more info. you will need to determine what is stuck, is it just the axle or something in the case. the axle can stick and the lite will be on but the case is actualy in 2wd . or is your case stuck and keeping the front axle engaged (like it should when in 4wd). does your shifter move into the 2wd position? or is it bound up when you try to go to 2wd (it will still work freely from hi/lo because these actuator shafts work indepentantly.) you may have a broken shaft or shifter.

just some thoughts for you to think over hope it helps.

 

^ to post above. The 4WD light on the dash is activated by the shift rail in the transfer case, weather it has manual hubs or ADD.
That means you can unplug the 4wd sensor on the transfer case and it will disable or unlock ADD, if it's functioning correctly.

 

correct! sorta. add is actuated by the switch in the t-case ( that would normaly operate the lite with manual hubs ) once add is engaged by the switch in the t-case the switch in the front axle turns the lite on. but i dont want to argue, ive been wrong before, so lets try to help this guy get his truck working.

 

I am trying to help this guy out figuring out what his truck is doing.
The transfer case switch, light and ADD relays are wired together. So by unplugging the switch on the transfer case the ADD system will "think" the truck shifted into 2wd. By doing so the OP can determine if the problem is the ADD system or an internal transfer case problem.