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Pontiac Grand Prix Transmission Problems



  • Hi, I tried to reverse my 99 Grand Prix GT out of the driveway this morning and the shifter seems to be stuck. When I apply my brake in order to engage the shifter from "park" to "reverse" the shifter seems to be stuck. I am parked on a slightly sloped driveway. The car starts fine however I can't seem to get it into any gear? Any suggestions would be greatly appreciated.
  • cnwcnw Posts: 105
    Sounds like you might be experiencing "torque lock". When parking on a slope, if the car rolls forward or backward in "park" after you take your foot off the brake, it applies tremendous pressure against the parking pawl--a pin that locks the transmission so it won't turn. Subsequently, when you attempt to take it out of "park", there is a great amount of side pressure against the pawl pin, thus making it hard to shift. Simple solution: Apply the emergency brake/parking brake BEFORE shifting into "Park". :)
  • i have a 2005 grand prix which i love but it seems to hesitate whenever i accelerate its happening more and more lately,any idea's
  • A few things that come to mind 1. check the spark plugs. 2. check the air and or fuel filter. 3. Bad gas (dirty gas) try filling up with "premium gas" throw some gas line cleaner in with the fill up.

    Try these things and let me know. Good Luck!!!
  • I was driving my Grandprix when it downshifted to passing gear I lost all gears but first. I got it back to my house then it set for a week. I had to move it when I got in it I had all gears back but reverse. When it gets warm I loose 2,3,and 4th again. what could cause this. I had no warning before I lost the gears
  • Watch that my car does not have reverse at all I put it in and the engine just revs and until the tranny gets warm I have all the other gears. once it is warm I loose all but 1st
  • I have a 2004 Grand Prix GT2. It has about 68,000 miles on it. Sometimes when I go from reverse to drive, then step on the gas, it hesitates. It doesn't do it all the time. I don't notice any other issues. Do I have a possble problem? I have an extened warranty to 72,000 miles, so if there is a serious problem, I can get it repaired.

  • Hey,

    I got a 2001 GRAND PRIX, aprox.150,000. the other day driving on the highway my car downshifted as i was passing a car as usual, but then never shifted back. i am currently stuck driving in 4th gear. could this be related to the software issue?
  • Hello,
    Im not sure if this is a PCM program issue or a pressure sensor issue? It hard shifts from 1 to 2 and sometimes 2 to 3. This only happens when the car is warmed up. I dont hear any wine like APPLE5 said.
    Thanks for any help
  • Hi, Apple 5 and all other pontiac guys

    I've been trying to find the part (Pressure sensor)[see post 90] for my car. The dealer thinks I'm nuts and doesn't know what part I'm talking about. Do you know the exact name, or a number for the part?

    I'm still shifting hard and whining away!
  • Hi All,

    I have been going through the forums and have found some great information so far. But I have not found any posts yet for my current problem. I have a '99 Grand Prix GT, and just rolled over 210,000 miles. I bought it with 80K on it, so I'm not positive but I think it is the original transmission.

    A while back I was told after an oil change that there were alot of metal shavings in the transmission, and that I should get rid of it right away. Since then I have put in some Lucas and have driven it another 15,000 miles. Occasionally I will feel it clank underneath when I accelerate, but only when I am already doing about 40 mph,not from a standstill. So now I have problems getting it into reverse sometimes when I start the car. I have to play with the shifter and the brake pedal, and eventually it goes right into reverse. (sometimes it doesn't do it at all)

    I asked someone about it thinking that it was the tranny finally taking the total dump on me. He told me that it was probably the interlock switch and has nothing to do with the inner workings of the tranny itself. When I squeeze on the shifter button, I can hear the clicking sound up to the dash.

    So has anyone else had this problem, and how did you deal with it? My friend told me that I could try disconnect the interlock switch and it should take care of it, but I'm not sure how to go about it. Also....on the right side of the shifter, there is a little plastic plug that says "shifter"'s faded and I can't read it all. Any ideas what that is, and what it is for? I don't have a manual.

    Lastly, I did put in an Astro Start last winter, that will shut off the car if you hit the brake before putting in the key.... Could this possibly be the culprit?

    Sorry for being so longwinded here....this is frustrating and I need to see if I can get this taken care of before I get rid of it. The car has always been great up til now except for this problem and the water in the passenger floor while the A/C is running. With this many miles I guess I should be happy..

    Thanks in advance for any advice with this problem..

  • I have a 1998 GT non supercharged grand prix, when the engine is under a load, you can feel a slight hesitation, several times, especially when going up a hill. i have replaced two of the engine coils (there are three) and this has not fixed the problem.Does anyone have a clue what to check next, I personally don't think it is the transmission, but have been wrong before, any thoughts. Was told to change fuel filter next. Thanks for any suggestions.
  • Just bought this car 3 months ago, I like it, alot. But, my 93 pontiac grand prix gtp has a 4T60-E tranny that has started leaking alot. It is coming from between the engine and the transmission. OK, so the front seal went out, fast. It has 100K and went from no leak to massive leak fast, 1 or 2 days. I have been told that if the front seal went out that means the oil pump isn't working and I need to rebuild the tranny or will just go out again along with other possible problems from the pump not working. It still drives fine. Anyone know if this is sound advice?
  • As stated above, my 1995 Grand Prix is having problems and will now not go in to any gear while running. I can move the shifter to any gear but it doesn't take no matter what gear. WHat could be causing this? Guess I have a big problem, huh? Would appreciate any answers anyone may have. Problem started Sunday when my car was driving fine and then would hesitate when hitting gas from stop (hesitate in to first gear); throughout the day it got worse and got to the point to where the car would rev real high but only go 30 mph or so; now, it won't shift in to any gear while running and also seems to have a little more trouble starting but does start. Thanks all.
  • I have a 1991 pontiac grand prix with the quad 4, the transmission will not shift out of first, and the spedometer quit working at the same time. Any ideas?
  • korkykorky Posts: 2
    I own a 1999 Grand Prix with 198000 miles on it, the tranny was replaced around 165000 miles. I was on my way back to college today when my car suddenly jumped up to 4000 RPM's. I was driving about 70-75 mph (usually between 2000-2500 RPM's) I called my dad, he told me to pull over, turn the car off, let it sit and then try driving again. After letting it sit for about five min, i started it up again and it was running perfectly. The rest of the drive it was fine(2 hours) and I got to a stop light about a mile away from my apartment. As I approached the stop sign and started slowing down, my RPM's jumped up to 4000 again, my foot was on the brake, not the gas. Then when the light turned green, I pushed the gas and my car started rolling backwards. We got the car in park, let it sit for a few min, tried starting it again. It drove fine for about twenty feet and then started doing the same thing again. It seems as if the car is in neutral. I'm thinking this is a transmission problem because this is similar to what happened to my car before. Is it normal to have to replace the tranny's twice?! Also, my car was in on Wed. for new tires, and a bunch of other stuff(end up being $900) They also did a transmission flush which I was told was needed. Now after doing some research on the internet I'm finding that transmission flushes can lead to things going wrong with the tranny because of the gunk that gets built up in there. Any thoughts? Any and all would be appreciated as I'm a struggling college student and don't really have the money to pay for another new tranny. Thanks =)
  • Hi. I was wondering if cars with the 4T60(non-
    electronic) are compatible with each other?
    For example a 1990 regal vs 1990 grand prix with the same engine etc. Also since mine has
    the 4T60 and not the 4T60-E will the electronic
    one work in my car? Are there any other things
    that I need to be concerned with swapping trannys? Thanks.
  • I have 58K on my GXP and the transmission has been hard shifting and missing for about a month now. Finally went out today and now I have to order a brand new transmission from Lansing at a price of $ 3400.00.

    Has there been any other GXP owners with similar issues with the transmission?

  • ae726ae726 Posts: 2
    I just bought a 2001 grand prix gt and it drove fine for the past 2 weeks, but I think I sense some foul play with the car. I know that they make a transmission stop leak, and such that you can buy from places like advance auto, and the dealership is one known for selling bad cars come to find out..The car ran like a dream, but slowly it started to act up, surging in second gear on flat roads, but as it is getting colder now it seems to be getting worse RPMs seem to be doing more exercise than me by the way they like to jump around.Especially when i'm going up hills that are somewhat steep, and along with the jumping, the car surges quite badly, almost like an asthmatic, trying to run a 50K if you get my drift, so if anyone is having similar problems, and knows a quick fix, or slow one for that matter,PLEASE reply!! Thanks ever so much,
  • ae726ae726 Posts: 2
    P.S my gt has 104,624k miles :0)
  • My car is doing the exact same thing. Just got the solenoid flushed and the catalytic converter changed and it's still doing the same thing. I read earlier on this post that it might be a software upgrade issue. Does anyone know if this is true??
  • To the above two posters:

    YES! Have your software checked out before you go any further. If Rob, who posted on here before me, hadn't posted what he did, my car would probably be long gone.

    The software upgrade costs $44 or so. I spent $1,500 before they found this out.

    Let's see: 1. Replaced some throttle thing - didn't work. 2. Replaced the solenoid - didn't work (twice). 3. Replaced the torque converter - didn't work. 4. Flushed out all the fuel injectors, replaced fuel filter - didn't work. 5. Replaced catalytic converter - didn't work. About 5 months, and $1,500 later ...

    6. Found this web site, read about the software thing - EVEN THOUGH MINE HAD THE "MOST CURRENT" SOFTWARE, IT REALLY DID NOT. GM had an unreleased new version they uploaded to my car.

    I HAVE NOT had a problem since. I am still driving my '99 GT and it runs like a dream again. So, by all means, explore this option. It fixed mine!

    If I can save anyone some of the headache and frustration I've had, that will be great.
  • I just got off the phone with the people from the Pontiac dealership. They told me to take it in to check the software, but the ran my VIN# and said that it had the "latest" software installed, but to take it in anyway. I'm going to print this whole thing out so he doesn't think I'm a lunatic and making this whole thing up. I'm so sick and tired of spending money on this issue :cry:

    And thanks for your reply :D
  • bettie2,

    My car had "the latest software" on it too, which apparently is faulty. Somehow, the tech got ahold of someone in Detroit who gave him a new version, which HAD NOT been released at that time. Maybe they have never released it?! I don't know.

    I just think you have to get the right person at the right time, who knows what he or she is doing!

    By the way, I do not have a Pontiac dealer where I live. I took my car to a Chevy dealer. In theory, all GM dealerships should have access to the same thing, but it might be worth trying another dealership.

    I hope they get it right. It took 10+ times for me. I understand how awful it is. :cry:

    I think GM should fix this for free!
  • Get the software checked. For more info, read some of my other posts on here.
  • Re. post #111, I did not see a reply, so I'd like to pose a related question. I have a 2002 GP SE with 71K. It has no transmission problems. Would you bring it in for a transmission flush? The owner's manual calls for 100K before a flush, but that seems kind of high to me, and I don't want to wait for a problem to occur. On the other hand, I'd hate to create a problem unintentionally. Thoughts?
  • korkykorky Posts: 2
    After getting my tranny replaced last week, my mechanic told me that if you are going to do a tranny flush on a car that has higher mileage you should bring it to an actual garage and not somewhere like Tires Plus. He also said that things can build up in the tranny and when it is flushed it can knock things loose(dirt, grime etc.) that are actually doing the car some good by holding things in place, and mechanics are going to be a lot more careful when they do it because they deal with this kind of stuff on a regular basis. I guess I would talk to your mechanic or do some more research on the internet before deciding what to do. Personally I will never have another one done again, one week without a car and $2500 later was just not worth it. Hope that helps a bit =)
  • I am having issues with my grand prix with the car when it is in drive mode losing power and bogging down. The dealer says the see the problem but there is no fix for the problem except to drive it in 3rd gear instead of overdrive. I argued my case with Pontiac on the phone and they will not fix it as they say there is no problem, but yet on my receipt they stated there was. I hope someone out there has the same problem and I can get this fixed. My car is only 8 weeks old. Also I have a brake issue with them clicking when first used and they say this is also normal . HELP???
  • I own a 2007 grand priz with 4000 miles on it. It has a surging problem mostly in overdrive but also in 3rd gear. You can watch the tack and it gets surges and the engine feels like it loses power and you have to punch it to get it to go. The dealer says there is no problem, to just drive my car in 3rd gear. This helps but doesn't stop it. Also I have never heard of driving a car in 3rd gear just to fix the problem. I have been in contact with Pontiac and they also say there is nothing they can do. I am so mad. I also had a second opinion of an "old school" mechanic and he says it is an electronic problem, somewhere. But POntiac refuses to check the problem. HELP??
  • I have a 2003 Grand Prix SE 3.1 with 150,000 miles on it. I have a PO742 code. When it is cold the tranny shifts fine but when it is driven about 10 miles and slows then starts the shifting it shifts hard, I mean hard all 4 gears. twice in the last week when slowing for a turn it didn't down shift it stayed in 3rd or 4th gear. I can stop and shut turn it off for 5 minutes and it will shift fine until it is drove for a few miles and have to slow for a turn or stop and starts then it starts the hard shifting again. When on the hwy and it has to shift to a higher gear (out of OD) going uphill it is as smooth as a new car. It shifts smooth until it gets warm. and sometimes it doesn't hard shift at all but that is rare. I have changed the filter and fluid. I am about ready to trade it off for something else. Anyone have any suggestions? What would it cost to have the trannny changed? I have a friend who has an auto salvage with one that has 47k on the tranny. fix or trade? :sick: I need a dependable car.
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