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Pontiac Bonneville Transmisssion



  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,511
    edited August 2010
    When were your spark plugs and wires changed? How many miles are on the car now?

    Because it seems to struggle after shifting, I'd suspect them first.
    Or, check each of the coils for corrosion in the sparkplug towers and on the prongs that insert into them underneath. Check the resistance on each and make a list. You can take the coils off one at a time easily. Sometimes coils give trouble when hot only. That's difficult to test for.

    You "mechanic" replaced the ICM, or I would have you check the connector on the end of it.

    When the car is doing this, stop. Turn the car off. Restart. See if it continues. I believe there was a problem with a computer control item that would reset.

    I would also take off and clean my MAF sensor without touching the two wires inside. Use a cleaner for MAF from auto store. I did use a camel hair artist brush when the wires were wet.

    After car has given the problem. Stop. Take off the engine cover and pull the vacuum hose off the FPR. See if liquid fuel comes out of the hose or if you get a strong gas smell out of the hose. The fuel pressure regulators sometimes leak extra fuel.

    Beyond that, you might have a fuel pump pressure problem. Sometimes pumps lose pressure when the pump gets warm after use and the fuel warms after being out in the hot ambient temps. If it doesn't do this driving when it's cooler, I'd take loan of a fuel pressure gauge with a long enough hose I can tape it to the outside of the windshield with duct tape and drive. See your typical pressures and see if there's a change when you car acts up.

    Beyond this I think you're at the wrong shop. The shop didn't diagnose. He hung new parts. Expensive.

    I think you need an up-to-date transmission shop that can watch the pressure control module and the various solenoids in the transmission during the shifts while driving it. A dealership who does transmissions would do this with their Tech II, I believe. A quality transmission shop also will have the same or better capability.

    Crankshaft position sensor?
    How many miles?
    Has it ever stalled for you? And then restarted easily or required a period of cooloff to restart?
    I think you would have mentioned a stall problem and you didn't. I would put CPS lower on the list.

    The EGR valve migh be acting up or sticking open slightly. It can be removed and checked. I believe it should have set a code for you and set the check engine light if it was not working properly.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • will a 95 & 97 pontiac bonneville transmission interchange
  • I just got my 99 Bonneville back from the shop yesterday. I took it in after a series of issues that started with a violent jerking after low speed coasting and stepping back on the throttle. It did this twice in a row, so I dropped it off at a local shop and they didn't come up with any fault codes. I drove it on home and used the car for another month, but noticed a few peculiar shifts especially after coasting out of a corner and stepping back on the gas.

    Monday I went to town in it and the Check Engine light came on, and it started shifting hard and a couple of time it just didn't seem to want to go after shifting. I dropped it back off at the shop and this time they informed me it was a torque converter and solenoid fault code which made since to me because of the way it was acting. They replaced these parts.

    I got the car back yesterday and all seemed well for the first 12 miles and the Check Engine light came back on, but it runs and shifting perfect. I took it straight back and they plugged it in and the transmission guy said it was the same code as before. He said he thought it hadn't had the computer reset.

    Does that make sense?

    He reset it and also said, "drive it and if the light comes back on it might be the throttle sensing..." or something like that. My wife took it to town today and after about 90 mile (we live way out) the light came back on again.

    It runs, shifts, and drives perfect, and just had a tune up about 200 miles ago.

    Does it make sense that out of the blue there is now a throttle sensor issue, or did they put in faulty parts?
  • the high idling could be just the out side air temp. i live in North Dakota and when i start my car in the morning it will idle at around 1500 RPMs. you can drop the idle by taping the gas to snap it out of the warm up idle. it would do this when it is 30 degrees or colder it seems with my car at least.
  • I have a 2000 Bonneville that started out a few months ago when you started it you had to wait about 5 minutes before it would shift out of park. One day while driving down the road it just stopped will run in 1st 2nd and reverse only. Does this sound like it needs to be replaced? The fluid is at the correct level and is pink. 165000 miles.
  • I'm having a issue with my car. When it warms up it begins to shift weird, mainly between 3 and OD. it will shift in to OD and the the revs will bounce. also wile going up hills in OD it will bounce the revs as little a 600 and as much as 1500 RPMs it seems like it wants to down shift but can't. If I let off the gas and then ease back in to it it shifts it self down to 3 and will cont with no problem. Any ideas?
  • crankeeecrankeee Posts: 298
    edited August 2012
    Buddy: We had a 1998 B'ville that started slamming and missing shifts. The first symptom only occurred when turning right AND going slightly uphill. Sounds strange but as it got worse it slammed and shifted very hard after over revving the engine. Took a very bright service foreman at the Pontiac dealer (Same as Buick, Chevy, Caddy) to diagnose the external shift solenoid on the AT. The screens clog up after some time and even a trans fluid change does not always get it. They replaced the external solenoid w/o dropping the trans so it was relatively cheap (vs. $2000 or more for exchange trans).
    If you get a good trans guy he will know about it. Yours may be an internal problem, that is more complicated. Good luck.
  • Last week, my car gave no warning & quit working! The motor locked up...there is no coolant in the oil. Someone thinks it might be the 'torque converter', any suggestions?
  • girongiron Posts: 1
    Hi i was having the same problem as you described did you ever find out what the problem was ? ive took it to 3 shops and they dont know what is wrong plz help

    2002 pontiac bonneville
  • imakelkatimakelkat Posts: 1
    I have a 2003 Pontiac it didn't want to go into reverse..i finally got it to go but lunges everytime I take off from a complete stop.its never done this before.could it simply be in need of fluid or such?
  • The check engine light can come on and stay on even if there is a very small air leak. If it runs fine and evrything is good i wouldnt worry bout the cel. I had an oldsmobile and even after i fixed some of the problems it jus stayed on. I wouldnt really be too worried.
  • If its lunging like a speedy bullet then if you took the cylinder manifold off and didnt replace the gaskets and torque it down to what its suppose to be it could have an air leak from the warped gaskets. Or possibly throttle position sensor is going bad
  • wesman33wesman33 Posts: 1
    I know this is a very old blog but for anyone searching for help and might read this. I had the same problem along with missing and stalling after it got hot and seemed like the tranny was shot. I took it to a transmission shop. they said i needed presure swith soliniod and touc converter lock up soliniod and i would be better off just getting complete tranny overhal. $2100 buck. huh i ended up relpacing mass air flow sensor runs like new car. I can not believe it $120 bucks for a carban remanufactured maf sensor. Make sure you dont get one of those $39.00 maf it might run worse. Good luck
  • I have a 2000 Bonneville, Trans worked fine then one day all of a sudden it was like I kicked it out of gear, would not take any gear until I completely stopped turned it off, set there a minute then started back up , put it in gear and pulled out. It was shifting fine for a few miles then it did the same thing again. It will take gear after you turn it off, then restart it. what could be causing this? Any info will help.
  • crankeeecrankeee Posts: 298
    My guess is that the shift solenoid is clogging up and when you turn car off it corrects temporarily. Any reputable transmission shop can fix it without the trans being removed IF this is the problem. My 1998 Bonneville was slamming and not shifting. Tech diagnosed it correctly and fixed it with new solenoid that had a revised screen on the inside to prevent fouling. good luck.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,511
    edited October 2013
    You don't mention the mileage or the maintenance history for the transmission. But assuming there's not a lot of negative there, it sounds like the transmission is losing pressure from the PCM.

    Is there a noise like a whine while it's doing this with the engine running?

    Does it reset to operate after 10 seconds or so and then turn the key on, or does it require a long sitting time? The computer control should reset if it picked up a code in a short few seconds of OFF time for the key.

    What does the fluid level look like when the transmission is warm, idling in park, level ground and you check the dipstick on the trans? It should be at the full level.

    Then what does the fluid level look like while idling when the transmission has refused to engage? Running, idling in park.

    If the fluid level changes during the problem occuring, that might help.

    What does trans do if you put it in the 1 position for hard first gear engagement? in 2?

    The FSM talks about several solenoids involved for various symptoms.

    But for dropping out of 3rd/4th low fluid level or low line pressure are first on the analysis algorithm. Line pressure might be due to a worn out Pressure Control Module, an item sometimes needing replacement in 4T65e's.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

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