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Chevy Blazer GMC Jimmy Maintenance and Repair

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  • Hey guys,

    I was wondering if it was common, or if you guys have heard anything about the transmissions in the 98 blazers going bad. Just last week my truck shifted out of 1st, but won't move out of 2nd. It will accelerate to about 45 mph, and then after that if you hit the gas it just revs real high, and won't come back down until you stop. Anyone have any insight into this problem? They are trying to tell me it is going to cost 2300 because it is shot. Can someone help me out??

    Thanks in advance!!
  • This may be related to your problem. As you can see, it effects many GM models with this model transmission. You may ask a GM dealer to see if doing this TSB would address your problem, since the valve body plays a big role in shifting.

    TSB # 01-07-30-023A
    Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)
    1996 Buick Roadmaster
    1996 Cadillac Fleetwood
    1999-2000 Cadillac Escalade
    1996-2000 Chevrolet Camaro, Corvette
    1996-2000 Pontiac Firebird
    1996-2000 Chevrolet and GMC Light Duty Truck Models
    1996-2000 Oldsmobile Bravada
    with 4L60-E Automatic Transmission (RPO M30)
    Built Prior to January 15, 1999 (Julian Date 9015)
    This bulletin is being revised to update the Parts Information. Please discard Corporate Bulletin Number
    01-07-30-023 (Section 07 -- Transmission/Transaxle).
    Condition
    Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon
    indicator is illuminated.
    Diagnosis
    Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.

    The scan tool may show a DTC P1870 set as a history code.
    A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when
    the transmission temperature is below 93°C (200°F).
    Cause
    The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the
    TCC isolator and regulator valves, and results in poor, or no, TCC apply.

    Important
    DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO
    CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
    When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure
    and harsh 1-2 shifts are the result.
    This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the
    second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
    When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as
    a history code.
    When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light
    (CEL), or Malfunction Indicator Lamp (MIL).
    Correction
    Install a control valve body with the revised TCC regulator and isolator valves. These valves are used in all
    transmissions produced after January 15, 1999 (Julian Date 9015), and all of the service parts currently
    available through GMSPO contain revised TCC regulator and isolator valves.

    Important
    If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace
    additional transmission components beyond the control valve body.
    Transmission operation is normal before the transmission reaches operating temperature, or before DTC
    P1870 is set (no slips, flares, or missing gears).
    The torque converter is not blue or overheated.
    The transmission fluid is not burned or has no burned odor.
    The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments
  • I had the same thing occur a few months ago after my Blazer was in to get the fuel sending unit replaced. As soon as I pulled off the lot, it would not go above 40 mph, no matter how hard I pushed on the pedal. I took it right back to the dealship, they hooked it up to the computer and found a code indicating the fuel filter was clogged. They replaced the filter and everything was fine. Being that this cost $35-$50, you may want to try it first...
  • homer76homer76 Posts: 1
    I have a vibration w/ my jimmy.I have changed tires x4, match mounted balanced, roadforced, all tires were ok. The dealer replaced Rear pinion yoke, driveshaft balanced. It occurs from approx 30 mph to above 70 mph. It's felt in the seat of the veh as with you shaking. Steering wheel has no shaking.60 mph seems to be the worst. Rear diffrential has been serviced, no metal was found or foreign material. Engine and trans mounts are ok. The veh is not used for towing or any exceesive work. Is in excellent cond, milage a little high, 38600. Very well maintained. Any suggestions for a shaking jimmy???
  • easheereasheer Posts: 5
    So my Blazer is 3 weeks old, bought it brand new, and this is now the third problem I've had with it. The other day I started the car, and the SES light came on. It was flashing, as I put the car in drive, the whole truck began to shake very hard. I shut it off, went about my day, came back about 5 hours later, started the truck, the light didn't come on, and the shaking was gone.

    What was this? Should I take this in to get it serviced? It seems like it is fine now, but I know nothing about automobiles, what do you all recommend? I don't want to damage something further, even thought the engine light has now gone off. Thanks!

    -e
  • Sounds like a similar issue that occurred on my '97 Bravada. I had a shifted belt in one of my new tires, and they were new Michelin Cross-Terrains! I had it replaced and the problem went away. This was after driveshaft balancing, rear pinion seal replacement, etc.
  • Have had the vehicle for a little over a year. Within the past few days I have experienced a problem. While driving the vechicle just shuts down. The power steering, breaks, engine, radio, everything. I have to cost it over to the side of the road. At first (this has happened three times now) the Jimmy would start right back up. Now it won't turn over at all. The battery light comes on. I've read many postings within the message board and am not sure what this might be. Does the alternator play a role in this? Could I need a new battery (it is one year old)? That past two times this has occured I was turning into and out of a parking lot, could this have anything to do with the problem? Any suggestions or advice would help out a great deal. Thanks.
  • I've got a humming noise in my 99 blazer that I was able to pin down to a grill above the driver. My dealer had no idea what I was talking about and offered to replace the sensor for a few hundred (P&L) but couldn't promise anything.

    Msg 425 seems to indicate the same problem with no solution. Has anyone else heard this? As Topdog says in msg 425 it's usually loudest just as you put the ignition into run (or whatever it is just before the engine starts) but sometimes I can hear it after the engine has been started.

    It drives me crazy, so if anyone has any thoughts I'd love to hear them. Would it be detrimental for me to snip the sensor? I find the automatic environmental controls never work right for me anyway (I want all AC all the time, baby!)
  • tbcreativetbcreative Posts: 357
    I also have a '98 Jimmy that I ordered from the factory, so I've had it for nearly 5 years and can tell you about all kinds of issues, including this one. It is definitely your alternator. I just had mine go out this last spring. My truck did all the same things yours is doing, and I thought for sure it was the battery, which would have been my third to die! Batteries don't last long in Phoenix, but I had just replaced mine about a year and a half before. I had a mechanic run a diagnostic on the power system, and it showed the alternator to be the culprit. I had it replaced, they recharged my battery, and that was that.
  • abc246abc246 Posts: 305
    I would not cut the sensor out of the loop. I am sure it would set some type of code and the system may not work well. This sensor reads the temp inside and (I think) has a small fan in it. What I would do is try to relocate it or put insulation around it to deaden the sound. Try to leave a path for air to get to it, if possible.
  • Thank you for msg #395
    Knowing where to look for problem took me about 1 hour to remove seat-4 nuts, 2 quick wiring connecters-and 4 bolts on power seat frame to get to exposed wires tape and reinstall. Really bad routing of wires.

    Have a rattling coming from underneath. Sounds like loose exhaust but I can't find anything loose. Anyone have this problem?
  • Hello guys. The Jimmy has a 2.8 L carb. v6.
    I looked for a diagnostic connector yesterday for about two hours. I'm assuming this truck doesn't have one. I thought someone on this site may be able to confirm that.
    We've been trying to diagnose a bad idleing & stumbling problem now for about three weeks. It's starting to wear on us a bit. I thought my OTC Monitor would help by giving us a trouble code, but we can't seem to find a ALDL anywhere.

    Any help would be greatly appreciated.:)
  • hengheng Posts: 411
    I don't think there would be much on board diagnostics. So even if there was a connector, you wouldn't learn much from it.

    There are a lot of vacuum hoses right? My first guess is a vacuum leak. EGR valve could be acting up too. The worst scenario is an electro/ mechanical part on the carb. You got wires going to the carb? There is an idle mixture solenoid that I had to replace which cost a bundle back then. Couldn't diagnose those smog engines either.
  • Howard, I appreciate the reply. Luckily for us, we do have an almost complete spare motor here. We did remove the EGR, & although it looked ok & the diaphram seemed to operate fine, we put a newer one on. Your first two guesses, vacuum leak(s) & egr were ours as well. We haven't found any leaks so far. We replaced the choke thermostat as well as the primary & secondary pull-off. It does seem to be running a little rich. We also have a spare idle solenoid we can try. I believe my buddy (it's his Jimmy) is planning on pulling the intake tommorrow. He's thinking the intake gasket may be leaking. He's had to replace this before on the other motor. Sorry for the length, & we really appreciate you replying. We are always open to additional suggestions.:)
  • I had a rattle that sounded like it was coming from the footwell. Well, the bushings/pins wore out on my '97 Bravada driver's door (common prob.) New pins and bushings cured the problem. May also be the hood hinge, which needs to be shimmed.

    A long shot may be the upper or lower ball joints, too. Had those wear-out, along with the idler arm and pitman arm at 46k miles (even though they were greased every 3-5k miles). There is also a recall for ball joint separation on '97 S-trucks due to corrosion, if you are in the Rust Belt.
    Hope this helps.
  • Don't know if anyone has experienced this problem. About two months ago, every time I started my 97 jimmy I would hear what sounded like water gurgling(best way I can describe it), only when truck was running. Did a complete forum search. Came up with possible radiator problem. (heater core) To make a long story short, Coolant recovery tank hose clogged with a brown gummy residue from Dex-cool coolant. When they say five years on replacement, they mean five years. Did a flush and new coolant. Seems to have solved problem. On my third alternator and no AC. I guess I am lucky. Also hood latch doesn't release all the time. Have cleaned and re lubed, no change. Any suggestions?
  • I have a 2000 Jimmy 4.3L SLE 4x4. I've replaced all the plugs, except I can't get to the center spark plug on the driver's side, the steering column is within about an inch of the end of the plug. I can get a plug socket on it but even if I could losten the plug I couldn't get it out with the socket on it... how do I do it? Do you have to loosen the steering column or an engine mount?
  • Since the rattling sound was only when moving and was steady (not affected by speed), the last place I looked was the drive train. Well, it's coming from the transfer case on the front drive shaft side. I turned the shaft and a consistent rattle came with each revolution from inside the case(only in forward-not in reverse). I bought this used and probably should have checked it over better( I can match most problems listed and have turned back into a part time mechanic with this vehicle). Turns out there was less than a cup of fluid in the case. I added a fresh quart, drove for a week and drained out all black. Added another fresh quart and am now driving with reduced noise. Have had a couple mechanics tell me to keep driving and noise may go away and the Haynes manual says the same. It doesn't seem to affect performance and I can get it into 4WD. Right now it's more of an annoyance than anything but I'm wondering if this is just the beginning and I should just replace sooner than later.
  • While the GM Service Manual does not indicate any interference from the lower intermediate steering shaft when removing the middle plug from bank #1, it clearly can't be done without its removal. Since the spark plugs for 2000 are slightly longer than those in prior models, its even more necessary. GM reminds the technician to maintain precise alignment of the shaft when it is reattached. The steering column must be locked in place and the position of the shaft to the upper intermediate shaft and the steering gear box should be marked before removal. If it is misaligned upon reattachment, damage to the SIR (air bag) coil assembly can occur. I believe removal of the lower intermediate steering shaft is preferable to jacking the engine from its motor mount (you may not get the clearance you need). It should be noted that the Service Manual does instruct the technician to remove the lower intermediate shaft for other service of bank #1 components, e.g. exhaust manifold replacement. I think we can conclude it is the way to go for removal of the middle plug. However, since the plugs are rated for 100,000 miles of service, I would reconsider the need to replace the plug unless it is damaged.
  • hengheng Posts: 411
    If I change tires sizes, what does it take to recalibrate the odo/speedometer?

    Use to be you just changed a plastic gear where the odo/speedometer cable entered the transmission.

    The 235/70-15 OEM tires really limit the available tires. I would like to go with the Yoko Geolander HTs but the closest size is 235/75-15.
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