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Chevrolet Blazer GMC Jimmy Transmission Problems

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  • Great, where do I find those posts?
  • steverstever Viva Las CrucesPosts: 41,297
    Most of them seem to be in the Chevy Blazer/GMC Jimmy: Problems & Solutions discussion. Try using the Search This Discussion tool for "ignition" to break them out.

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • I have a 1998 blazer 4 wd automatic. It does not have 2nd gear or go into overdrive. I have replaced three of the soleniods, the 1-2 shift, the 2-3 shift and the 3-2 shift solenoids. This has not fixed the problem. Should I replace the govenor pc valve?? The oil was not burnt and no major amount of shaving found in oil. It does not shift hard or have any funny noises. I am stumped!! please help. :confuse:
  • repairdogrepairdog Posts: 948
    Hope I am wrong - did you lose reverse, 2nd, and 4th gears? If so thats the weak part in the 4L60E trans called the sun shell and the neck breaks off and trans rebuild time. See the tciauto site for pics and more info. If have reverse then suggest a trans shop attach their diagnosis tool and pinpoint the piece.
  • brenr3brenr3 Posts: 2
    I have a 98' Blazer with 75K miles on it. The transmission has shifted smoothly up until about 1 week ago. When I start the truck and begin to drive, it shifts smoothly. After a few minutes of driving, the battery light comes on and the airbag light flashes. They both go off after a few seconds. The next time I come to a complete stop and accelerate, the truck shifts very hard between 1st and 2nd gear and continues to do so until I turn the truck off.

    Example: Last night I began my commute home from work, the truck shifted smoothly. While waiting at a stop light, the brake and airbag light came on again. The truck shifted hard between 1st and 2nd gear the entire drive home. I parked the truck in my garage and went inside to get my wife. No more than 5 minutes later we got into the truck, turned it on and went for a drive. The transmission shifted smoothly as I drove through my neighborhood. This morning, I started it up, it shifted smoothly until the lights came on again. What is up with my truck? I have a hard time believing it's the tranny, it has been completely fine up until last week.
  • repairdogrepairdog Posts: 948
    Sounds like 2 diff problems. Get the transmission filter changed and that will get you 5 qts of new fluid and a clean pan (has a magnet in it to catch small shavings) which usually fixes this hard shift caused by a TCC unit that usually gets crap in it and then the pump goes to max pressure so hard shift. Also possible TPS on throttle body acting up - this tells trans throttle position to shift at.
    Airbag light could be from a bad connector in column, or on the two front under frame mounted sensors, or the fuse.
  • brenr3brenr3 Posts: 2
    You think it's two different problems even though the truck only begins to shift hard after the airbag light and battery light flash for a few seconds, then go away?
  • how do you get the darn thing out lol
  • Same answer as in the other post.
  • tmillsdtmillsd Posts: 2
    HELP, I have changed the transmission (new) all shift sensors and still have the same problems as the old transmission, will not shift into higher gears (automatic), does shifts ok in 1 and 2 but no higher.I am at a loss. So in other words it was not the transmission but something else.
  • repairdogrepairdog Posts: 948
    There is a transmission help site online that would probably be more help. I have no clue what trans was behind that beast - isn't that the 454 and if so a 700R4. Beleive it has a modulator assembly on the passenger side but....
  • my 95 jimmy will drive fine until i hit 3rd gear. it wont shift out of second. it never made any noise or grinding. someone had told me to change the throtle possition sensor but i want some better info and what other people think i should try.
  • repairdogrepairdog Posts: 948
    Will still shift but roughly even if the TPS is failing. I would get the pan dropped and chage the filter, clean the pan out, and refill the 5 qts (out of about 11 - others in the converter) and see if that fixes it. Each gear has a shift solenoid that performs the shift and the 3rd gear one may be stuck or failed - trans shop has a scanner to tell and they usually do the scan for free and do the trans filter for under $100 - its a messy job at home due to no drain plug.
  • my97jimmymy97jimmy Posts: 15
    Well...now it's my turn for transmission problems. I hope someone can help.

    Scoop: I have a 1997 GMC Jimmy w/4 wheel drive, automatic transmission, V6 vortec engine, and 155K miles. Trans fluid and filter was changed at 80K. The trans worked fine yesterday, but today it's stuck in 3rd gear.

    Additional info: I can manually shift it into second gear and third gear, but no first gear or overdrive. Reverse works fine. Also, twice this morning when I put it in park and shut it off, I couldn't turn the ignition to off to get the key out without starting it back up and working the shifter thru the gears a couple times.

    Any help would be greatly appreciated.
    Keith
  • my97jimmymy97jimmy Posts: 15
    Follow up to my post #40.

    Now I'm confused. I read somewhere to disconnect the battery and let the computer reset. So I did and now my trans shifts fine. What's up with that? Does anyone know why?

    Great, I think my Jimmy was made by Microsoft. Just had to reboot it.

    Thanks in advance,
    Keith
  • steverstever Viva Las CrucesPosts: 41,297
    In the old days (before Microsoft), we called that sleep engineering. Funny how it seems to work all too often.

    In your case you probably have an "adaptive" transmission that just relearned how to shift, and hopefully that's all it took.

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • repairdogrepairdog Posts: 948
    There is an adjustable shift block on the linkage on the trans side (follow the cable) that could be off alittle. Then the deal with the key worries me - the 97 (only) has a known ignition switch (connector and wiring in column) that acts up and can cause all sorts of strange problems so if more occurs would point to that - look it up on most auto sites and a pic shows you.
  • my97jimmymy97jimmy Posts: 15
    Well...300 miles since I rebooted my Jimmy and the transmission is doing fine. Linkage looks fine (not loose or worn) and haven't had problems getting the key out either since the reboot. Thanks for your help guys. See you next problem.
  • My brother owns a 1995 Jimmy V6 Vortec 4.3 4x4.
    He just had tranny rebuild and installed and is having problems with first gear, overdrive and 4x4 does not work. All these worked prior to new tranny.

    We have heard 4x4 could be a vacuum line leak and replaced most vacuum lines, and the problem still exists.

    We have heard that first and overdrive could be a wire problem, is this true? Hooked it up to a scanner and it did not show anything. I have read through the postings and my brother is going to try disconnecting the battery like the '97 Jimmy and see if that works.

    Any other ideas, would be appreciated. :confuse:
  • repairdogrepairdog Posts: 948
    Whoever did the rebuild and install is responsible for delivering a fixed working vehicle or don't pay them.

    You probably have a 3 button np233 transfer case so that was pulled to get the trans out. Make sure the 3 port vac switch works on the transfer case and all lines good. Are all the electrical connectors firmly plugged in? Check the wiring bundle above the trans for cuts - seen that. Look at the throttle position sensor on the throttle body for linear operation (resistance smoothly changes as the TPS/throttle opens). Each shift and convertor lock has a separate solenoid in the trans pan.
  • timprobtimprob Posts: 1
    My 97 Jimmy , automatic 4x4, won't shift until it winds out past 3000 rpm's. This just started. It drives fine if I use 1st, second, third then Od manually shifting. It won't shift on its own. I don't want to take it to a transmission shop, because here in Michigan, they are notorious for ripping people off. Any suggestions would be appreciated. Thanks, Tim.
  • my97jimmymy97jimmy Posts: 15
    Tim, I know nothing about transmissions, however I had a very similar problem with mine. I was told to disconnect the positive battery cable and wait 10 minutes for the computer to reset then reconnect it, start it up, and take it for a drive. I've put 500 miles on it without a hickup. I was told that the computer has to re-learn how to shift. Also, check the trans fuse on the fuse panel on the side of the dashboard by the drivers door. It's a red 10amp fuse. Good luck! Keith
  • repairdogrepairdog Posts: 948
    Sometimes that helps but when was the trans filter and fluid last changed - at least every 50k miles is the norm. Hope that clears it up or possible shift solenoid sticking (one for each gear). Fuid level to full. Also possible TPS on the throttle body has a dead spot (resistance changes as throttle opens/closes) so PCM does not know where the throttle is and then trans shifts at internal default point.
  • mkobmkob Posts: 10
    I have a 99 Jimmy 4x4 with 125k miles and just the past few days I have heard a low ticking noise when I put my Jimmy in reverse or drive. This is a different noise than what I am use to hearing and don't know what the cause can be. I have had my transmission serviced within the past year and still under 50k miles. Could anyone please tell me if this is a bad noise?
  • repairdogrepairdog Posts: 948
    Depends where the noise is from - have to narrow it down alittle. Is it trans, lifters (oil/filter clean and no water loose - if res drops possible lower intake gasket leak starts with a lifter tap), idle or tensioner pulley, alternator bearing going, PCV, etc.
  • mkobmkob Posts: 10
    I have replaced the idle and tensioner pulley, alternator, changed the oil within 100 miles, the intake gasket is new, the fan is new, the spark plugs have been changed out, the PCV has been replaced - I think that is it. I was parked on a slight hill and it only made the sound when I put it into reverse and drive. I opened the door and it was coming from the engine portion of the vehicle, not under the vehicle. Without having someone standing there with me that is the best I can do at the moment.
  • repairdogrepairdog Posts: 948
    Was the AC on when you heard it?
    How about the water pump - have a helper put it in reverse and you listen - see where its from - watch the hands when its running.
  • ramdodge1ramdodge1 Posts: 3
    I have a 1998 GMC Jimmy, it shifts fine and even into overdrive... but after a few moments after, it comes out of overdrive and back in. It will do it more frequently when tranny is cold. I have been told that it may just need adjusting and I have been told it cant be adjusted. Any help on this will be greatly appreciated... Thanks!
  • repairdogrepairdog Posts: 948
    There is a solenoid for each shift and convertor lockup accessed thru the pan, but the first thing is the fluid full and has the filter been changed - could just be crap in the system. Then there is a throttle posion sensor on the side of the throttle body that tells the trans throttle position and shift point based on that can go bad (dead spots its just a cheap resistor pot).
  • ramdodge1ramdodge1 Posts: 3
    Thanks for the reply repairdog, I will get the filter changed and then go from there. Talk with ya soon.....Thanks again!
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