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GMC Jimmy 4WD Problems



  • four wheel drive is supposed to work anytime on ground or not. let me see. did you check acuator under battery. make sure cable from front differential is not sticking. I had a bad cable and it pulled out of the acuator. made a popping noise.make sure your cacume switch on transfer case is not sticking . but sounds like you have vacumn problems.
  • Had a lot of trouble this year with four wheel drive on 1998 jimmy. had to changed acuator acuator shift cable for acuator and encoder motor for transfer case, didn't have four wheel drive at times. changed dash switch. four wheel drive works good but now dont want to shift from four high to two high. have to cut ignition off then back on to get it to shift back to two high. How can i fix this. reboot by taking off battery posts or do i need a part all vacum parts are new and have new vacum lines dont know what else to do help me if you can.
  • do I need to change front axle sensor switch in dash dont want to shift from four high to two high in 1998 jimmy. changed switch in dash and acuator under battery shift cable and encoder motor on transfer case. before i changed switch didn't have four wheel drive but switch worked before i changed to new one. Do I have to unhook post from battery and wait ten minutes or what. Can anyone help on this?This winter has brought out the worst in my jimmy four wheel drive. Good thing it worked when I had to drive in 20 inch snow.
  • my 98 jimmy wouldnt go into four high but lights on switch said it was. I changed acuator. acuator shift cable. encoder motor on transfer case and does go into four high now after I changed the dash switch. It fixed it but now it dont want to shift from four high to two high unless i cut ignition off then it will switch back to two high ok thanks if this helps but im still trying to figure this out
  • my 98 jimmy doing the same thing only it will go into four high then dont want to change into two high light just blinks goes back to four high. i have to cut off ignition then try to get it back to two high. im afraid im going to get stuck in four high. I think i will have to change the encoder motor on transfer case. How did you fix yours
  • mine is doing the same thing sticks in four high dont want to shift to two high. I have to cut off ignition switch and wait awhile then go to two high or some times go from four low to two high before it will disengage. can anyone help me figure this out all vacume lines ok acuator and shift cable are new. changed encodermotor but maybe its going bad too. I didnt even have four high till i changed dash switch
  • mine is doing the same thing i have 1998 jimmy had to change dash switch before four high word work. now dont want to shift from four high to two high. do i need front differential sensor too. need help
  • kadkinskadkins Posts: 1
    I have a 98 Jimmy with the 3 button 4wd switch on the dash. When I try to change it from 2wd to 4wd or vice versa, it blows the fuse under the hood. But this ONLY happens when it is hot outside, after driving for a few minutes. After it cools off, I can change the fuse and it works fine, until it gets hot again. I didn't have one problem with it all winter...I could drive it all day and it would still change just fine with no blown fuses. So far I have changed the vacuum hoses, checked the electrical connections to the TCCM, and changed the actuator vacuum motor under the battery. Since I cannot get up my 450ft driveway without 4wd, it is pretty important that I get this fixed quickly. Any suggestions?
  • anyone know why my push button switch on dash dont want to shift from four high to two high. put new dash switch in. and acuator under battery and shift cable. what else do i need. would not go into four high till i changed dash switch.
  • mine is doing the same thing 1998 jimmy dont want to shift from 4 high to 2 high. I changed dash switch acuator and acuator cable. but didnt have 4 high till i changed dash switch. thats when it didnt want to shift from 4 high to 2 high. what else do i need to change
  • Anyone know who makes wiring harness for transfer case. My 1998 jimmy dont want to shift from 4 high to 2 high. Have to keep switching the switch and cut ignition off at times. I think I have narrowed it down to the wiring harness. gonna try that nest. Hope someone know how to fix this. I changed acuator. shift cable. vacume switch on transfer case and changed encoder motor and checked front axle shift sensor. Whats next
  • jt88jt88 Posts: 1
    hi i was just wondering if you ever figured out your issue with your jimmy because i have a 99 jimmy with similar issues just wondering if you could email me back to give me some tips about this that would be apreciated

  • tidestertidester Posts: 10,059
    email me back

    Let's keep the discussion here so everyone will benefit. :)

    tidester, host
    SUVs and Smart Shopper
  • I guess I have narrowed my problem down to the connector on the encoder motor on the transfer case. Everything else seems ok. Wiring harness problems will be my next step. But the weather is better now so I don't need 4 wheel drive till winter. WILL let you know what I find out.
  • The best thing I can think of making it vibrate is your drive shaft u joints. Check those being a 75 model I'M pretty sure thats probably the problem.
  • hey mine was doing the same thing this winter. Leaving me spinning in two wheel drive. I changed acuator under battery. acuator cable to front differential and transfercase encoder motor . and still didnt have four wheel drive some times. then I changed dash switch and now it dont want to shift from four high to 2 high. But thank god I had four wheel drive when I needed it. Now I think its in the wiring harness to the transfer case motor . gonna try to see if that does anything. this winter has cost me hundreds. let you know if this fixed mine
  • Try a dash switch to see if that works. mine didnt want to go into four wheel drive till i changed it but i think my wiring harness is bad. let you know it that was my problem
  • woods12woods12 Posts: 1
    Looking for a wiring diagram for 1994 GMC Jimmy for the 4wd drive system, vacuum and electrical would be great, anyone have such a thing.
  • Koz you need a acuator front axle shift cable. can get one from napa about 25 dollars. thats where I got mine. hope this will help
  • wnekwnek Posts: 2
    I am having a problem with my 4x4 in my jimmy, this is the model with 4
    button 4x4 dash console,I had been without 4x4 for a bout 7 months and
    finally came across a part I needed which was the TCCM computer, after
    replacing it my 4x4 started working ..., it worked for about 1.5 months
    and I am having issues with it again.,
    what is happening when I first installed the TCCM I heard 2 clicks from
    the box upon the ignition start and the 4x4 was working great shifting
    all modes, however after a while my service 4x4 light came on again and
    I was stuck in 4 hi, after checking the connection to TCCM replugging it
    I was able to free my truck off 4 hi to 2.
    Now I am scared to even switch , I noticed upon te ignition start the
    TCCM now clicks 4 time and goes into blank mode showing "service 4x4"
    dash light..., I am gonna inspect all the hoses today and the vaccuum
    actuator, I also tried to clear the computer unplugging the battery for
    more than 1 hour...., can anyone help , what do the 4 clicks coming from
    TCCM mean ??? ,
    Could that be some electrical problem ??? I also noticed that in my
    Jimmy when I turn the ignition half way to get the dash on with the
    radio the TCCM engages and then when I start the engine it resets and
    engages again.. , is that normal ??, how many clicks should the TCCM
    make on vehicle start, when it was workinig it made 2 clicks upon
    ignition start and again 2 clicks upon engine start, now its double at
    each stage and it goes into the service 4x4 mode...
    any help would be greatly appreciated.


  • My 98 jimmy gave me a fit this winter. Found out it was the encoder motor on the transfer case, Hope next winter will spare us all the trouble. Thanks for the help in this chat room. Kingstonsman
  • I have a 2000 jimmy ,I noticed the lights on the 2wd 4hi 4 lo buttons were not lighting up and when I change to 4wd nothing happens could this be a electricial problem ?
  • my problem was the encoder motor on the transfer case was not working maybe this is your problem too. My dash switch said i had four hi but i didn't then it wouldn't go back to two high. changed the encoder motor now works fine. Hope it works good this winter. thanks
  • hi well today i also noticed the inside lights are not working as well . i checked the fuses inside the truck and all are good I am goin to test under hood fuses as soon as i get a test light (in am) thanks
  • I am fixing my jimmy and need to know what a part is callled to order it no one seems to know what I am talking about. It is about 2 ft long the driver side axle bolts on it and has to do with changing gears in 4wd and have to keep grease in it. Does anyone know what I am trying to find out the name of it. maybe even a picture to let me know I am looking for the right thing?
  • I have the same problem with my 96 Jimmy. Did you find out what the problem was?
  • my 1998 gmc jimmy shifts from 2 wheel to 4 wheel lo but not to 4 wheel hi . anybody know why
  • I had a lot of trouble last winter. It was my transfer case motor not working right. But you could have other problems too. Like the front axle shift cable sticking. Mine stuck and burnt up my transfer case motor. Or encoder motor as they call it. Good luck fixing it. A couple months from now you will probably need your four wheel drive. Kingstonsman out
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