manually dissengage 4x4?

Discussion in 'Trucks and Trailers' started by mike lane lawn care, Nov 4, 2007.

  1. mike lane lawn care

    mike lane lawn care LawnSite Bronze Member
    Messages: 1,707

    ok, so the other day my truck got stuck in 4lo, after a few cycles of the ignition, the truck allowed me to get out of 4 lo, and into 2hi. what it did was all the lights on the pushbutton 4x4 switch went out, and the display center said "service 4wd" it is a 1999 GMC sierra new body style, with pushbutton 4x4 with autotrac II. today while towing on th highway, the "service 4wd" message came on again and the truck dumped itself into 4hi, and all the indicator lights that tell you what drive mode you are in went out. but i knew it was 4hi by the way it is steering and handling. i can't figure out how to get out of 4wd, i assume it's the switch, which in GM's has a history of failing. i ordered a new one but it won't be here for several days. does anyone know how to manually dissenagae the 4wd and put the truck in 2hi, so i can go to school and work tomorrow without risking blowing up a driveline component?

    by the way, it came out of 4x4 for a few mins today, only when i really needed it. i was pulling my stuck tractor out of a muddy yard that the owner had forgot to mention that the yard had flooded recently. i got the truck stuck and got pulled out by the owner's 4wd toyota highlander, it was very embarassing, so yea, it's been one of those days.

    thanks a lot guys.
  2. AndyTblc

    AndyTblc LawnSite Fanatic
    Messages: 5,480

    atleast it didn't kick into 4lo, that could have been bad. I have a 99 old body style, and it has 209,000 and I haven't had any problems with that at all.
  3. fool32696

    fool32696 LawnSite Senior Member
    Messages: 993

    Sometimes when I'm in 4hi and push 2hi it will indicate that its out of 4wd but still be in it. I can usually get it into 2wd playing with it for a min or two. I have a GMC 2500hd with duramax/allison
  4. Cooter

    Cooter LawnSite Senior Member
    from NE Iowa
    Messages: 510

    I had the same problems with my 99 2500 Silverado. I now own a Super Duty w manual hubs. I also had a 89 2500 that had similiar problems with the electric actuator on the front axle. After several new actuators I replaced it with a Posi Lock manual unit. That was the best thing I ever did to that truck.
  5. FearThisDeere

    FearThisDeere LawnSite Bronze Member
    Messages: 1,154

    I'd check your hubs.
  6. LindblomRJ

    LindblomRJ LawnSite Silver Member
    Messages: 2,570

    Sounds like it might be an actuator that controls the transfer case. Take to a shop have them plug the diagnostic tool in to see what the problem is.
  7. TXNSLighting

    TXNSLighting LawnSite Fanatic
    from DFW, TX
    Messages: 6,464

    gms are known for this. you have to take it to the dealer and they have to clear it out. my friends 03 duramax did this. the service 4 wheel drive light was on all the time. and when it was the 4x4 wouldnt work. dealer said leave it for a day with us and well fix it. 6 months later he took it in and they fixed it. some malfunction in the computer system.
  8. meathead1134

    meathead1134 LawnSite Senior Member
    Messages: 637

    This is why I still like manually locking hubs. I know numerous people where either they were stuck in or cannot get into 4x4 because of the computer problems or a bad switch. I've got a 98 GMC 2500 with a lever on the floor for the T case.

    BTW This is the exact reason why I passed on the newer body style.
  9. MarcSmith

    MarcSmith LawnSite Fanatic
    Messages: 7,157

    i have 03 tracker(not really chevy i know) but it has the manual transfer case, and while it was still under warranty I could move the transfer case and 4hi 4lo, but the truck would not shift it was the result of the actuator in the front drive line still not letting go into gear. so 4even with the older styles, and it looks like a manual transfer case, there are still some electronic buggers that keep you screwed up...

    I guess you could always remove the front drive shaft.....
  10. Dirt Digger2

    Dirt Digger2 LawnSite Silver Member
    from PA
    Messages: 2,396

    we had the same problem in a 2004 F250, it wouldn't come out of 4lo...just kept grinding the T-case

    this is why i hope they never top making manual hubs and manual T-cases...electronic shifting t-cases are just no good, i think...i will always like pulling a lever rather then pushing a button, even if it means getting out in mud to lock in the hubs

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