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Chevrolet Blazer GMC Jimmy Transmission Problems

larenz71larenz71 Member Posts: 8
I just bought my blazer and transmission is leaking. After purchase of blazer guy tells me it was a non op. What should I check for first , how should I approach.
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    repairdogrepairdog Member Posts: 948
    86 Blazer don't know what you mean exactly - it works or doesn't? Sounds like it just leaks - if so look at the level on the dip stick, check the vent on top for the tube and cap, vac modulator on the side has a diaphram and vac line up to the engine, pan seal, rear seal, and front seal (that one will see fluid dripping out the bellhousing up front - requires trans be pulled to fix).
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    blaze4x4blaze4x4 Member Posts: 29
    (2001 Blazer 102,200 miles) Well, I replaced the rear driveshaft U-joints (at the rear axle, two of the cups had rust inside), but I still have a harmonic vibration that seems to cycle. For whatever reason, this morning on my way to work, it started out REAL bad. As thing warmed up , it subsided, but was still there. Any history of a torque convertor going to pot on these Blazers. As bad as it was this morning, I gotta a feeling I'll soon know whats causing this, something is going to let go!
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    repairdogrepairdog Member Posts: 948
    Could be the rear pinion bearing, transmission, or actual driveshaft out of balance. I always get mine spin balanced when replacing both U joints - they tack weld a small weigh on it. Looks like a 4wd and that output is thru the transfer case so they do have problems. If an LT with Autotrac the fluid is special blue synthetic called Autotrak II at dealer and its to quiet cluch pack chatter in the transfer case. Did this problem start and then you changed the u joints as a first shot? Is vibration speed related and seat of the pants or steering wheel shack? Could be tires if worst when cold. Had out of round rear disc/drum and they caused a hopping shack over 60mph.
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    larenz71larenz71 Member Posts: 8
    thanks for the advice i do appreciate it. ;)
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    blaze4x4blaze4x4 Member Posts: 29
    I don't use the E brake at all. Last brake job, put new rotors on all four corners... seems like an out of round drum section of the rear rotor would have shown up then. The vibration was there prior to replacing joints. It is an Autotrac (4 button selector... 2Hi, 4Hi, 4Lo, Auto4wd). You don't suppose that as bad as the rear U joint was that it took out the pinion bearing (currently 102,300 mi.)? The vibration is always there, just some times worse than others. Most noticeable at speeds of 55 plus mph. Was on the expressway last weekend, and like to rattle my teeth out.I had the trans flushed, filter replaced at dealer ~22,000 miles ago. Vibration in the seat of the pants. I didn't replace front shaft u joints. I was told that until vehicle is in four wheel drive, shaft doesn't spin, is that true?
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    repairdogrepairdog Member Posts: 948
    I have one of these exact Blazers and they are known (sorry) for some vibration problems. Often nearly impossible to find/fix:
    1. If not done already, change that front u-joint also and balance the driveshaft.
    2. Have your tires force balanced that is computer read and it shows out of spec tires and heavy spots - 1 in 10 tires are often so far off they should not be used and sees bent rims/heavy spots in them too.
    3. Check the trans mount and engine mounts for separation.
    4. Put the Blazer rear end on jack stands and drums/disc on with at least 2 lug nuts, with a helper start and put in drive and you watch the rotating drum/disc and see it perfectly round and no oval - mine were - new ones are usually cheap China junk and I've had several bad ones recently as I've done 4 complete brake jobs in the last year on mine.
    5. Check the rear calipers slides - bet you did not grease the pins in the brackets and they hang up and eat the inside of the rotor and drag. Also hope you put rebuild calipers on those rears cause they are a cheap single pison one that cocks in the bore and hangs often too.
    6. Flush the transfer case and add the blue GM Autotak II syn fluid, and then drive 100 miles, reflush and add 2 new quarts - GM bulletin on this.
    7. Have you replaced the lower ball joints - #1 weak spot, and looked at all steering jonts and greased all of them.

    Thats a quick shot at some of the things to look at.
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    blaze4x4blaze4x4 Member Posts: 29
    Looks like I have my work cutout for me. Although I didn't replace the rear calipers, I did remove the slides, wire wheeled the clean (yes, they'd been hanging up!) and greased (heavily). Earlier this spring, had upper and lower ball joints replaced, along with the idler arm and front end alignment, just before having the intake gaskets and thermostat replaced. Tires AND wheels are new (will have rebalanced). Thanks for all the suggestions. I'll pick away at them one at a time and let you know what I find.
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    larenz71larenz71 Member Posts: 8
    I changed transmission fluid added a stops leak oil as well.I do have a knock that almost sounds like a diesel motor.It is not the motor, motor is strong. I was thinking possibly transfer case,drive line or axle.Am I close?
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    repairdogrepairdog Member Posts: 948
    86 Blazer so 2.8L V6 motor? Is the sound always there even when not moving (in park)- if so rules out drivetrain.
    Any smog pump on it? Vac hoses rotted out or leaks? Exhaust leaks, flange gasket, muffler. Need more info on the when/where/etc for noise. Crawl around and listen and post some specific clues for me.
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    larenz71larenz71 Member Posts: 8
    The sound appears to be coming just center of the motor itself.Sound remains when waiting at a light but as i accelarate it stops brief moment .I will get underneath tomorrow to see where pin point is.Thanks
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    larenz71larenz71 Member Posts: 8
    The Blazer did come with street tires not 4WD and they are small.I never even stop to think the tires could be main starting point as for the vibration.
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    ajw121ajw121 Member Posts: 2
    I have a 97 blazer. About 2 months ago it started jumping out of high gear on the highway. Since then i have had the transmission rebuilt. Now It still jumps out of high gear, But if i stop and turn off the engine for a few minutes then restart it. High gear works again. sometimes for a short time sometimes longer. But it always works again, at least for a short time after i restart it. Any thoughts? All i seem to be getting is the run around and no straight answers.
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    repairdogrepairdog Member Posts: 948
    I am not a trans expert but there are solenoids that control the shifts and are you sure its dropping out of 4th or is the converter unlocking - feels like a shift?
    Any good trans shop can test these so.... maybe time to change shops. Keep trying.
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    lightningsteedlightningsteed Member Posts: 7
    My 2000 Jimmy slt 4.3L auto shifts really abruptly when its hot usually after I've been sitting in stop and go traffic (which happens too often I'm in Southern California) sometimes it shifts so hard it chirps the tire normally I might mind that but I feel like its going to self destruct anyone else have this issue?
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    repairdogrepairdog Member Posts: 948
    #1 is get the filter changed in the trans and that replaces about 5 qts of the fluid. Valoline Max has high mileage fluid that I use. This may solve the problem. If it does not (it has on 2 of mine) then GM has a bulletin on the TCC bore wear that contains the TCC isolator and regulator valves fixed by dropping the pan and Not a full rebuild. Find a good trans shop and ask questions - normally all trans built after 15 Jan 99 have these updated so look at your production date on the door sticker.
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    mrgorkmrgork Member Posts: 2
    In my 01 blazer the 4wd electronic controller switch changes on its own, it gets stuck in 4wd low and won't change manually back to 2wd. Is there some kind of electronic control in the transmission that would cause this or is it a bad switch? Has anybody else seen this before? There is also an electronic problem with the gauges, the tach does not work, the gas gauge will fluxuate from empty to full to empty etc, this may not be connected but I thought I should mention it just in case.
    Thanks
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    repairdogrepairdog Member Posts: 948
    Look at the 4wd problem answers posted but if this is in 4Lo that means the encoder motor is engaging - hope not when moving - so is it in 4Lo? Check the wiring on the side of the transfer case and see if it is cut/ripped/nicked - seen that and causes that type problem. Also a sensor on the transfer that tells the TCCM (computer in the cab pass side kick panel) low/high gear status. Front axle has to couple too. Again after the wires are fixed, disconnect the battery for 30 minutes and see if the TCCM reboots/resets.
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    mrgorkmrgork Member Posts: 2
    When I disconnected the dashboard switch it brought it into 2wd, I'm pretty sure its just a bad switch, I'm gonna try replacing that to start off.
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    zzkvslzzkvsl Member Posts: 1
    I have a 2000 Sonoma with 50k miles that the trans wont sift in Drive. When in Drive at a stop it will not go into gear. but whrn I manually shift into 1st or 2nd it will engage, then while driving I can manually shift into 3rd then Drive and it will move thru the gears. when coming to a stop (in Drive ) it will not down shift into 1st. I again have to manually shft into 1st or 2nd to move. Do you have any idea what the problem may be

    thanks Mark
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    97blazer4wd97blazer4wd Member Posts: 1
    I have a 1997 4wd Blazer that is stuck in third gear. It will shift into park and reverse fine. Vehicle has only 32500 miles on it, but has been sitting for about the past 2 years til recently. I have put approximately 1000 miles on it with no problems til now. Any ideas? Thanks
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    repairdogrepairdog Member Posts: 948
    Pull the codes and see what they are. Check the adjustment on the shifter cable on the side of the trans.
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    repairdogrepairdog Member Posts: 948
    Pull codes from trans. Have filter replaced and pan cleaned - long time to sit. 97 (only) have a known ignition switch (name but actually the ign module in the column) that can cause many problems with many componenets.
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    skruphiskruphi Member Posts: 3
    gotta 99 blazer 2 door 4wd 4.3l The transmission knocks when stopped in drive but does not knock in neutral or park, whats going on?
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    repairdogrepairdog Member Posts: 948
    You sure it really is the trans and not some engine part as thats when the rpms drop as the converter loads up. Check fluid and if you have never changed, as most, do the trans filter and fluid thats first and see whats in the trans pan. Then as a helper puts it in drive with foot on brake and e-brake on look under the hood and see if he AC compressor or alternator is dragging. Shut off and look under hood again at the belt and AC and alt. Then if its only when you first put it in drive thats a GM trait due to clearance in the rear diff, or u-joints if worn out, or transfer case.
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    skruphiskruphi Member Posts: 3
    ok ill try changing the fluid, gottanother one for ya, when turning at low speeds right wheel makes one loud pop every once in a while??
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    repairdogrepairdog Member Posts: 948
    Lower ball joints are the #1 reason - jack it up and grease them and uppers and the other zerks on all the linkage and have to remove the front plastic skid plate to get to the idle arm front one - like 10 or so total. If that doesn't do it look at the CV axles are the boots ripped and any grease coming out. Then the hubs, brakes, or the classic hood shifting at the hinge bolts - yes GM added a spring washer to each side to fix so carefully place a rag in between the fender and hood and close (do not bend anything and see if thats it.
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    blazerfamilyblazerfamily Member Posts: 1
    99 blazer 2 wheel drive, never had a transmission problem until the intake manifold gasket leak was repaired. Immediately after repair transmission will not shift properly. Goes in and out of gears at will during all speeds. Occasionally wont start. We checked fluid level everything is okay. Not sure what was done to make this happen all of a sudden when I have NEVER had a trans problem. Any suggestions!! I am scared I am going to mess up my transmission. When I am on the highway I have to lift my foot off the gas in order for it shift gears. Also when I shift gears , it shifts real hard.
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    repairdogrepairdog Member Posts: 948
    Probably they did not connect a sensor properly after the intake done so all lines and connectors need to be rechecked. Shop should do it that did the intake. Could be a vac line leak also. When was the trans filter last changed (every 50k)? 4L60E trans do have some known hard shift conditions due to dirty fluid and a TCC solenoid problem but often a filter change fixes. Finally any SES light on and codes?
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    castellanocastellano Member Posts: 2
    I have a 1997 Chevy Blazer. Got it for a steal! Truck has 138,000 miles on it and was a highway driven vehicle I bought from a friend who I trust when he tells me he had no issues with it. soon after I purchased it the fuel level gauge stop working. I replaced the level sensor with a genuine GM part and the gauge works but bounces when I turn on the turn signals? First problem :(

    We towed my boat to and back from Canada with no issues other than the bouncing fuel level gauge and since then have driven the vehicle for approximately 5K miles. My wife broke the hazard switch and the heater core started leaking a little, no real problem that I can not deal with. Now the vehicle intermittantly stalls while driving just like someone turned it off however the electrical power remains? Most of the time after it stalls it starts right back but sometimes lately it is difficult to start. I really do not even know where to start? The fuel pump sounds normally at ignition start. I am confused please help?
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    repairdogrepairdog Member Posts: 948
    Again, see all the posts on the known 97 only problem ignition switch (the connector and wiring acually) in the column - not key/tumbler - so do that first. May solve all problems.
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    castellanocastellano Member Posts: 2
    Great, where do I find those posts?
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    steverstever Guest Posts: 52,454
    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.
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    jettemanjetteman Member Posts: 1
    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:
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    repairdogrepairdog Member 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.
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    brenr3brenr3 Member 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.
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    repairdogrepairdog Member 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.
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    brenr3brenr3 Member 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?
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    brucehayslettbrucehayslett Member Posts: 4
    how do you get the darn thing out lol
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    repairdogrepairdog Member Posts: 948
    Same answer as in the other post.
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    tmillsdtmillsd Member 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.
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    repairdogrepairdog Member 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....
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    jdoylerlzjdoylerlz Member Posts: 1
    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.
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    repairdogrepairdog Member 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.
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    my97jimmymy97jimmy Member 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
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    my97jimmymy97jimmy Member 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
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    steverstever Guest Posts: 52,454
    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.
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    repairdogrepairdog Member 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.
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    my97jimmymy97jimmy Member 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.
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    brosjimmybrosjimmy Member Posts: 1
    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:
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    repairdogrepairdog Member 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.
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