1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

Stuck in 4X4

Discussion in 'Truck & Equipment Repair' started by B&E snowplowing, Jun 30, 2010.

  1. B&E snowplowing

    B&E snowplowing Senior Member
    Messages: 159

    Good day all,

    I have just purchased a (now don't laugh) 1989 Chev 3500 HD 4X4 with dump box. I think it might be stuck in 4 wheel because the light on the shifter is lit up, and the truck sound like its in 4X4.

    Now this truck is a diesel, and I have never owned anything this big, so I really don't know how it should ride, but I have shifted the shifter from 2wd to 4 hi to 4 low and back to 2wd and the light still stays on.

    Can anyone tell me if I crawl under the truck and disconnect the connector to the 4wd actuator will that disengage the 4wd.

    Is it possible that the shifter or light could be screwed ????

    Any help or ideas would be great.

    Thanks all, have a great day!!!!

    Happy Canada Day!!
    Brian
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Just noticed this one Brian. Did you get it sorted out or still need assistance?
     
  3. B&E snowplowing

    B&E snowplowing Senior Member
    Messages: 159

    Nope haven't got it sorted out yet, actually, I had to go away for Canada Day so I haven't had a chance to look at it yet.

    Have you got any ideas, it really does feel like it is in 4X4 when you get up past 45 - 50 mph.

    Thanks, looking forward to your reply.
    Brian
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    I doubt the T-case is actually engaged thus locking the front and rear axle together and sending power to the front otherwise it would be extremely tight in the turns. Most likely it's just the actuator that's engaged hence it's spinning all the front end components at those road speeds, which you can usually feel on most trucks and lets you know something isn't right.

    The most fool proof way to do the diagnosis.....

    1) Raise and support the front wheels off the ground. But before you do, turn the key to the run position and leave it there while your getting the truck in the air. Be sure the T-case shifter is in the 2WD position as well.

    2) While the ignition is still on slide under the truck and turn the front D-shaft by hand while watching the front tires. If one or both rotate when you turn the D-shaft then the actuator is engaged when it shouldn't be. And if this is the case- turn the ignition off and wait a few minutes and re-test again. If the tires now do not rotate then the actuator is being told to engage any time the ignition is on which isn't correct, and this is because the switch on the top of the T-case that commands it is stuck thus it's sending power to the actuator any time the ignition is on regardless of what position the T-case shifter is actually in.

    3) To test the switch- disconnect the electrical connector from it (it's near the top on the driver side of the T-case right above the T-case shift lever). Then turn the key on again, wait a few seconds and turn the D-shaft again. If the wheels now do not rotate with the D-shaft then that switch on the T-case you disconnected is defective. Simply screw it out and replace it with a new one. They do fail from time to time and it's certainly no shame on a truck this old.

    Let us know how the diagnosis turns out.
     
  5. B&E snowplowing

    B&E snowplowing Senior Member
    Messages: 159

    B&B,

    I will try that as soon as I am finnished up with supper, and will get back to you...

    Thanks for your reply and help.
    Brian
     
  6. B&E snowplowing

    B&E snowplowing Senior Member
    Messages: 159

    B&B,

    I have checked out the truck and the front left tires rotate with the key on and off. Now I really baffeled.

    Your professional opion PLEASE!!!!

    Thanks
    Brian
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Sounds like the actuator itself is stuck in. Not too common for the old style heated actuators to stick in the engaged position but it can happen. There's also a return spring in there that can break too, thus when the actuator releases the shifting fork in the axle tube it isn't shifted back to the disengaged position.

    Using a large adjustable wrench go ahead and fully remove the actuator from the axle and do the D-shaft test again and post your results.
     
  8. B&E snowplowing

    B&E snowplowing Senior Member
    Messages: 159

    Hey there B&B,

    A great BIG thank you for all your help....I finally had the chance to get under the vehicle to remove the 4wd actuator, and noticed right away that the previous owner CUT the wires on the actuator, so I pulled out the actuator, and he had a cotter pin in the shaft of the actuator, so that it was always engaged, I removed the cotter pin reinstalled the actuator and the front wheels stoped turning when I turned the front drive shaft. I have ordered a new one at a cost of 210.00. All is well though as I feel better knowing I have one that works and is new.

    Thanks again for ALL your help it is greatlly appreciated.
    Brian
     
  9. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Happy to assist as always Brian. Sounds like there may have been an issue with the actuator at some point so the previous owner simply "converted" it himself. :D

    However I'd be still be a little suspicious once you get the new stuff on there as it's a bit odd for someone to hack all the wires off. Perhaps there's an electrical issue somewhere that they could not solve so as a preventative means they simply chopped the wiring to it. So be on the lookout for that once you have it back together and if there is an issue still we'll continue to get you fixed up. :waving: