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Pontiac Bonneville Transmisssion



  • Hi I am new to this group, I find it great that you can come here and , with alittle help people can see the light at the end of the tunnel as they say. But i to have a 1994 bonneville, 220k Changed fuel pump, fuel filter , spark plug and wires and i think the coils were changed before i bought it, but my problem is overdrive, have done alot of reading , but dont seem to see an answer , gets to a certain speed and starts to feel like trany problem then if you put your foot into it it stops, or if you let off, has anyone found a fix for this??
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    > then if you put your foot into it it stops, or if you let off,

    Can you describe more about what and when it's doing when you say it stops or if you let off?

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

  • The ''buckin'' like its trying to shift into or out of overdrive....

    thanks for the reply.
  • I just resolved the "bucking" problem with the 4T65-E transmission on my 2002 Bonneville with 135,000 miles. This problem has multiple causes, but the main one is jammed shift and EPC solenoids. The jamming comes from particulates accumulating in the solenoids and impeding their functions. The particulates come from the overdrive and 3rd gear clutches burning out. Also, the bucking and, in my case, jolting, also came from wear in the 2nd gear spline, drive chain, boost valve, and channel plate sleeve.

    I asked the transmission specialist where I took the car if more frequent maintenance would have helped, and he said that while I could have gotten a few more miles out of the tranny by more frequent fluid changes ( I was changing at every 30,000 miles), these transmissions start failing at between 125,000 and 175,000 miles. Also, to completely repair the transmission is not cheap, at least not in my particular case, but it was less expensive than the down payment on a new car, and since financing a new car is next to impossible right now, and that I'm not ready to part with my Bonneville, I look at it as a new lease on life.

    1994usedbon, may your problem be less expensive and less extensive. The 4T65-E transmission didn't come along until 1997, so your experience may be much different. Good luck!
  • jgrovjgrov Posts: 1
    i have a 1999 boneville ssei and every time i accelerate it jerks in every gear is there something i can do and it also jerks when i shift to neutral what could be the problem?
  • I have 2003 Bonneville. It has about 130,000 miles on it and I do not know if the transmission fluid has ever been changed. The fluid levels are at the right level. Recently the has incurred a slight noticable lunge when shifting through the gears. I have been reading in the forum and curious if it is the Transmission Valve Body or the Transmission Torque Converter Solenoid. I am also going to change the Transmission Fluid. Are either of the parts external or are the inside the Transmission.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    How's the motor running?

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

  • The torque converter solenoid is internal. Of that, I'm certain. I'm not sure about the transmission valve body. After having multiple problems with the 4T-65E transmission on my '02 Bonneville last year, it's likely that major issues concerning jolting, lunging, or jerking when moving between gears is going to be caused by an internal component. Good luck, and hope your problem turns out to be an inexpensive one.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    I repeat: How's the motor running?

    Have the plugs and wires been replaced at the 90-100K mileage as specified in the owner handbook? Plugs AC iridium same as originals?

    Are there any other parts that are not working quite right? MAF sensor might be one?

    Does the throttle body need cleaning and that extra goop blocking the bleed air around the throttle plate affecting how the IAC can control the very low speed mixture?

    Before blaming trans, always make sure the motor is up to snuff. Then it's time to be sure the transmission is doing what it needs.

    There also are a few who feel a motor mount wears and allows more movement giving more unevenness to the shifts.

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

  • I have replaced the spark plugs, wires, new air filter, new fuel filter checked all of the fuses, changed the oil in this car. Sometimes when I start it takes several seconds for the engine to turn over and start the car. When I apply the accelerator it fires right up. I have also been using high octane fuel and a fuel additive. I have also used Lucas Injector Cleaner. The vehicle does get better fuel mileage even gotten 450 for an 18 gallon tank half highway. I do have a slight oil leak near the head. Also the slight jerking happens in cycles not all the time. Sometimes it shifts just fine and sometimes I can feel it noticably.

    Also the engine will sometimes stop running if left to idle for about 10 minutes. Once while the hood was open I noticed a slight puff of air/steam come near the water pump and intake. Any suggestions?

    To add to this... the service vehicle soon light comes on and off every few days. It has also been dying when turning slow turns or u turns. I assume the power steering is using up the last bit of power causing it die.

  • am having problem with my tranny about 1 year now , when the car is cold the tranny will not go into no gear.will go after 10 min and shift fine like there is no problem.i change the fluid same problem.the engine run like dream
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    That might be a terminal sign or might just be the pressure control module. I'd get a diagnosis from more than one transmission shop to see. I wouldn't try just one because they might try to lead you to a rebuild. I believe you have a 4T60E transmission and I believe, repeat believe, those pressure control modules can be replaced without taking the transmission out of the car.

    Do some searching for pressure control module and transmission will not go in gear and see what you can learn.

    Good luck.

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

  • When I start my 02 Bonneville and take off it wont shift gears. After driving it for a while it will finally shift and then after that it runs fine. Once it get over that first hump it is fine and runs like a champ on the highway. The odd thing is when I leave int the morning I dont have this problem, but when I leave my office for lunch or leave for home it does it. Any ideas what it could be?
  • car has 100k miles appears to stay in second gear ,wont shift runs good engine wise. dealer says pcs about 1000 dollars. aamco says build trans about 2000 dollars . all of dash has went haywire Any IDEAS?
  • I have a 2000 Pontiac Bonneville SE with approx. 138,500 mi on it. I bought it last year and the transmission had a little jerk to it. I had an engine mount done and it seemed better. I had 3 sensors go bad which caused my car to really jerk. I replaced the high and low idling control sensors and a pedal sensor. Since then, I would have to let the car warm up for about ten minutes before driving so it would not jerk. After the summer, that manipulating technique stopped working. I replaced the VSS and there was no change. My check engine light is not on so I am trying to figure out what could cause my transmission to jerk. I did change the fluid and filter, I also had a tune-up done months ago. I am lost. I was thinking about replacing the transmission speed sensor. Any suggestions?
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    I would say check all connections for the positive and negatives on the battery. Check ground on rear floor by loosening and retightening. Check positive connections at the front fuse block in engine compartment by loosening and retightening.

    I would consider putting in a new battery just to see if it makes a difference.

    I would consider a rebuild an lifetime warranty if it does turn out to be the transmission.

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

  • is the solenoids for the 96 sse external or internal and if so how would it cost to replace my car is hesitant when you drive it what could be the problem
  • emeachamemeacham Posts: 3
    I was curious, if anyone had any idea what could be wrong with my transmission. I've had the car for 5 years, had the tranny flushed 3 years ago, radiator replaced 14 months ago, and regular oil changes every 3500 mi-- 5-30 fully synthetic. Car has ~174k miles on it, no other real issues. It's been a great car.

    I've been having issues with the tranny for about three years. Started because the shop that flushed it said there were no leaks, but caused a leak when they reattached the hose to the bottom of the radiator's cooling reservoir.

    I've been waiting for it to just go out... but it's just not happening. It bangs (slips?) into gear-- 2nd to 3rd, sometimes 3rd to 4th --after it's warmed up. I've had it into the shop 3 times, 3 different places, and all of them tell me they don't find anything wrong.

    I drive an hour to and from work, 5 days a week, and there are days when I will have no trouble. But then there are days were I will go 5 miles, and it starts doing it. It doesn't make sense to me. :(

    I am tempted to just get it and the motor rebuilt... anyone have any thoughts or recommendations?
  • I had this problem two years ago with my 2003 bonneville. I had the tranny filter changed new fluid hoping this was the problem. It did not take cre of the problem but made the problem less noticeable.

    When I would be driving and mainly when it was on a up shift it would jerk like it did not want to go into gear or it was confused and didn not know what to do.

    I finally went in and had the PCS changed pressure control switch. This took care of the problem has been a year and have had no issues witht he tranny.

    hope this helps
  • to gregjudy90: thanks! I will definitely try this! Will keep you posted.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    Pressure control module?

    Also, if you shut off the car and immediately restart and continue to drive with the transmission all warmed up, does it go away for a while and then come back. I recall someone talking about a problem that sets a computer fault which is cleared by restarting.

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

  • I have this same problem with my 2000 Bonneville. What exactly did you do to repair this problem. What is the PCS and where is it located. My email is
  • alitobaalitoba Posts: 2
    I had a 97 Pontiac Bonneville and got involved in a serious car accident two weeks ago. The insurance company is offering me very litle money, what I've contested. They"re now asking me to provide them with proof of the car value.
    Any idea about the value and how to get proofs.

  • emeachamemeacham Posts: 3
    edited June 2010
    Sorry for the delay, but thank you very much for the reply.

    To answer your question, sometimes it is worse after turning the car off then back on... sometimes, it doesn't start UNTIL the car is turned off then back on. I've recently started having issues with the service engine light coming on, too... says the Fan 2 relays on my ODB2, but I've replaced all of the fan relays/fuses (~$200) and it still is an issue; I cleared the message, and it came back a few hours later.

    I will report back with findings; have to get the Bonne scheduled for a check-up.
  • phoenix86phoenix86 Posts: 3
    Hello, I am looking for some advice. I have had my Bonne for a year & a half and my tranny seems to get worse the longer I have it. I have done the fluid & filter change regularly. As of late my throttle position sensor has been acting up. I replaced it with a new one from the dealer & it seemed to help my tranny shift better. But now my car is idling high and my check engine light goes on and off by itself. This high idling problems has been prominent for the past 3-4 months. Sometimes I have to start my car a few times before I can pull off to reset the computer (I guess?) and my car typically will drive fine for awhile. I have noticed when I run shirt errands that it runs smoothly.

    Is there any correlation between the throttle position sensor and transmission?
    How likely is the problem my computer?
    Could it just be my tranny?
    Please, help!

    ------------I have replaced the shift solenoid and PCS------------------ :mad:
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    edited July 2010
    Sounds to me you might have a vacuum leak. I believe those will sometimes set a code or light. But I think the code I heard didn't obviously appear to come from a vacuum leak, but when analyzed it made sense. This is why it's important to troubleshoot anything before replacing parts. The box parts stores have started shying away from just letting people buy parts after running the code checks on the cars for them. I've heard counter guys helping people analyze the meaning.

    Check all around the perimeter of the upper intake manifold. Check all rubber hoses and connectors for cracks, softness, hardening, especially on sides toward hot motor where they might deteriorate and not be visible. The vacuum leaks can cause a high idle. With the upper intake, as it warms, it expands and may be sealing a leak or crack.

    You can use a carburetor spray around the areas where leaks might be with the motor idling. If there's a leak the extra hydrocarbons sucked in causes a change in idle speed and sound.

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

  • cverboskycverbosky Posts: 1
    Need help I have 2003 Bonneville when I"m driving it comes in out of gear sometimes you just let off the gas and it goes back into gear other times u have to put her into netural then drive and she goes find this happening like every so often is the tranny shot?
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,497
    How many miles and what kind of service in the way of trans fluid drains and filter changed?

    Whst does the color of the transmission fluid on the trans dipstick look like?

    I would say I've changed my 2003 leSabre at 35K and 70K. I put in Dexron VI which is a synthetic blend that replaces the original fluid Dexron IIIe (I think that's right, check the back of the glovebox manual). That means with a drain and fill that only about 50% of the fluid is replaced. That's good. New additive cleaners to pick up stuff collecting in places where it's affecting the operation but not a totally new 100% shock of lots of additives. I do not believe in the flushes that shops like to do.

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

  • My 99 bonneville runs great normally but at low speeds when the transmission shifts in and out of 1st/2nd/3rd gear multiple times in short succession (i.e. rush hour traffic) bad things happen. The transmission will shift hard and acceleration is hesitant or non-uniform in the higher gear. Once I let off the gas completely and ease on the petal the acceleration is OK (till the next shift). Basically I pretend like its a manual and try to time up letting off the gas at the shifts (15mph and 25mph). Then after my car sits overnight the problem goes away.

    My mechanic replaced the ECU, ICM, manually checked the voltage levels (he had it for 2-3 weeks), and flushed the transmission fluid. After this did not fix the problem he told me that the transmission would likely need to be rebuilt eventually. After researching the issue I want to replace the crankshaft position sensor in any attempt to avoid rebuilding the tranny. Any knowledge you can share would be an enormous help as I am pretty much on my own to solve the problem.
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