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Tranmission not liking upper gears?

M

marlize

New member
Not sure where to start but hopefully my fellow *awesome* Grand Prix owners can help me out. I have a 2008 Grand Prix GXP with 130,000 miles. I drive 120 miles daily - all highway miles. I know, my poor car :( I don't think this has anything to do with it, but I was in an accident around April of this year where my front end was just bleah. It made it through though and the engine was not touched, by inches. After it was fixed, I had tons of issues with my car overheating, leaving me on the side of the road, etc. I had to get stranded 8 times or so before it was finally fixed - some type of leak that kept being missed because it was coming out to the exhaust - dont' ask me. I couldn't make sense of it. I also had my engine light come on and off a few months ago. I can't remember the code but according to the mechanic it was some 02 sensor that causes you to fail the emissions test but it never came back and he made sure it was working so it was never changed.

So, my real issue. I had been noticing recently that when I would be at a complete stop and would accelerate, my car would be slow to react, then jerk itself into gear. It would happen randomly and lately had began happening every other day.

I just came back from a vacation - drove 1,000 miles total this weekend with no issue. I went to yesterday on my usual 60 miles to work and I began noticing my car just felt weird. I would reach 65-80 range and my car would feel like it was buckling, even on cruise control. I immediately thought of my transmission, especially because of the jerk I mentioned above. I had always heard that I needed to get my transmission flushed at 100K miles and I never did so I figured this may be why. I drove it slowly to work and afterwards, went to the Kwik Lube near my work and asked them to flush my transmission. The fluid was a gold brown and they did it.

So, today, I have not yet felt the jerk from first (which I consider a good thing) but now, still feel the weirdness when driving from 65-80 range. So, I tried a bit more things to see what it was and let me see if this makes sense. I was at a stop, accelerated and felt my gear change after reaching 2500 rpm or so. I guess this is first. I kept my foot on the gas and it reached 2700 maybe again and switched fine. I BELIEVE (may not be - I just know I was going 55 or so) I was in 2nd going to 3rd or 3rd going to 4th - not sure since I am not good at this but the RPM gauge would not go over 2000RPM. It felt like it was pushing. I kind of pushed gas harder (I prob shouldn't have) and it jumped to like 2400 hard and my car felt like it buckled. It was in whatever gear this was and it feels horrible. Like, rocky and shaky and jumpy. Its weird to describe.

Any ideas? It only does it when it reaches this gear or higher speeds. Is my tranmission going out? :(

One thing I should mention, around a year ago, I had taken my car to get my oil changed and the guy came out and asked if there was a trick to putting my car into drive because IDK what he did but my shifter was just going up and down the gears and not actually going into gear. It would stay in Park (as shown in my display). We saw what it was. The "arm" that comes out and moves when I move the shifter and connects to the part that changes the gear in the transmission was no longer connected. I got my car home and I purchased the cable and just shomehow replaced the small connector piece instead of getting a mechanic to replace the entire thing. It worked and it's still connected so I don't think this is the problem. Sorry - I'm not good with car vocabulary.

Any ideas please?
 


Usually the 65-80mph issue you describe is a tune up being needed or a sensor giving the pcm an odd reading. I'd suggest scanning it for codes and let us know if you have any.

The prior O2 issue etc shouldn't be related, same with the shifter linkage.
 
I think a couple of things are happening..lower engine mounts are compromised along with you feeling dod kicking in and out. There's some thing gxp's need to operate healthy. Transmission coolers, fluid filter changes...no flush!!!...and shift kit/and or tuning.also get your mounts expected
 
Well I took it to a local transmission shop for an inspection and they called me today to tell me that it was "most likely" some part in my transmission that locks and unlocks when driving steady speeds. Did not get a clear understanding yet and will most likely find out once I get there.

He seemed to concentrate more on the fact that my RPMs fluctuate rather than my car feeling like it's pushing - may be the same thing. I do notice it when on cruise control or driving a steady speed that my RPMs would jump and down about 500 RPMs. Its strong enough to have me feeling like the car is rocking. They said the best way to find out would be taking the transmission out and then they would be able to know if replacing the part would fix the issue or if they would have to rebuild the transmission. :/
 
Let's pretend that I know something about these cars and maybe swapped a trans because of a similar issue.

If you are going to spend that kind of money on it, you really want to ensure that it's not something silly, cheap and small causing the issue and while the torque converter lockup is kinda common.....many times you'll find that doing a simple tune up fixes the issue. Meaning.. it's often ignition related and not transmission.
 


I am hoping it is something small. I'm willing to try all the small things before thinking of taking the transmission out. What would a tune up entail? I'm a girl and don't want to get taken advantage of.

Not having a good week with my poor car and sorry a55 men trying to take advantage. When I got my transmission flushed, I had the guy at the place come in and tell me he was so sorry but he broke the handle to my glove box. :th_angry2: Why he was even near my glove box while he was doing a transmission flush is BEYOND me.
 
Also, what is the norm for transmission fluid? I've hit 214 before but keep seeing that normal is 180. I live in Houston so it is usually hot here but not sure if that would mean it's alright for the temp to be that high.
 
1811 is max adapt shift. This means that the trans saw an issue and the way that works is when it sees an issue, it automatically jacks the pressure for adaptive shifts to max. This usually gives you quite a jolt at the shift and makes you take it in for service.

The code resets (no longer current, but remains in history) with an ignition cycle, so the problem has to be recurring if you keep feeling harsh shifts.
 


Well not actually feeling harsh shifts anymore. I'm not sure if it says when that code came up - wasnt there a week ago and have tried not to drive it but yesterday morning had the weirdest thing happen when taking it to the mechanic friend, which may have triggered the code. Started my car up, waited maybe thirty seconds, placed it in drive and it was going but I was literally jumping up and down, could hear a loud clunking nose as the car moved and it was shifting hard, to where I was literally being jerked. Tried to video it but video didn't come out great. Turned my car on and off and it was gone. strangest thing.

Mechanic did confirm it was not going to third and in his opinion, it was most likely the transmission but was going to do some research he said. Reason for my excessive gas usage solved.
 
Yes, apparently it was the torque converter and I had burnt clutches among other things. Got the transmission rebuilt for $1300. It's driving amazing right now. I hope this is the end of my problems :)
 


Take the time to install a transmission cooler and shift kit/and or tune.of else you'll find ypureself in the same position very quickly
 
So, back again :(

Had to take my car back because my Check Engine light turned on. The error was a P0742-TCC System Stuck Off. First, they said they just needed to reprogram the computer. After a week, they said the computer will not let them reprogram it. Supposedly, my car's computer keeps kicking their system out. Now they're saying the "PCM/ECM has gone bad". Odd, I did not have my light turn on before I took them my car and now it won't go away.They have supposedly tried to "help me out - at no cost" by trying to find me a new computer for free from salvage yards from people they know but every one they try, does not work.

They said that if it comes to having to go to the dealer to get my the computer, it will be $700. I just want my car back and am thinking of paying it but am also trying to find out if this is too much and if this even sounds right? I am upset because my car did not have the light turn on at all. I can't find anywhere else where a Grand Prix needed a new computer or how much it would cost. Could someone help me?
 
marlize said:
So, back again :(

Had to take my car back because my Check Engine light turned on. The error was a P0742-TCC System Stuck Off. First, they said they just needed to reprogram the computer. After a week, they said the computer will not let them reprogram it. Supposedly, my car's computer keeps kicking their system out. Now they're saying the "PCM/ECM has gone bad". Odd, I did not have my light turn on before I took them my car and now it won't go away.They have supposedly tried to "help me out - at no cost" by trying to find me a new computer for free from salvage yards from people they know but every one they try, does not work.

They said that if it comes to having to go to the dealer to get my the computer, it will be $700. I just want my car back and am thinking of paying it but am also trying to find out if this is too much and if this even sounds right? I am upset because my car did not have the light turn on at all. I can't find anywhere else where a Grand Prix needed a new computer or how much it would cost. Could someone help me?
Click to expand...
take this info to them: To me it sounds like they didnt repair your transmission correctly and need to take it back apart but heres the technical info you need to take to them. remember these people will say or do anything to get out of having to do any more work on your vehicle you need to be firm with them and not let them put blame on you after they take your money for something they did incorrectly.

The transmission control module (TCM) controls the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. The solenoid controls the hydraulic fluid for TCC apply and release. When the TCC is fully applied, the engine is coupled directly to the transmission through the TCC. The TCC used is an electronically controlled capacity clutch (ECCC). The TCM normally allows a small amount of slip to occur with the ECCC. When the TCC is engaged, TCC slip speed is maintained at approximately 20-50 RPM. The 1-2 shift solenoid (SS) valve and the 2-3 SS valve are supplied with fused ignition voltage. The ground path is controlled by the TCM. When the TCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the TCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure. The TCM identifies a 1-2 SS valve or a 2-3 SS valve condition by monitoring the commanded gear versus gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .
[h=3]Conditions for Running the DTC[/h][h=4]P0742[/h]
• No TP sensor DTC P0120 or P0220.
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• No ISS DTC P0716 or P0717.
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• No OSS DTC P0722 or P0723.
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• No TCC system stuck ON DTC P0742.
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• The engine speed is greater than 500 RPM for 5 seconds.
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• The transmission fluid temperature (TFT) is between 20-130°C (68-266°F).
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• No TCC system stuck OFF DTC P0741.
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• The calc. throttle position is between 8-90 percent.
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• The TCC PWM solenoid valve is commanded OFF.
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• The gear ratio is between 0.66:1-1.68:1.
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• The engine torque is greater than 50 N·m (37 lb ft).
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• The vehicle speed is 16 km/h (10 mph) or greater.




  1. Perform the Transmission Fluid Check .
    ⇒Correct the transmission fluid level if the fluid is not at the proper level.
  2. Using the scan tool, clear the DTC. If DTC P0742 was set, operate the vehicle greater than 72 km/h (45 mph) with the Calc. Throttle Position between 8-90 percent and use the scan tool to command the TCC OFF. Observe the TCC Slip Speed parameter on the scan tool. The TCC Slip Speed should be greater than 60 RPM.
    ⇒If the TCC Slip Speed is less than 60 RPM, inspect the following components and repair or replace as necessary:
    [h=4]P0742[/h]
    • The TCC control valve stuck in the apply position

    • The TCC PWM solenoid valve stuck, exhaust restricted, or faulty internal O-ring

    • The TCC fluid circuits leaking--Refer to Control Valve Body Disassemble .

    • The TCC blowoff valve or spring for damage or not seating--Refer to Case Assembly Inspection .

    • Turbine shaft seals for leaks--Refer to Torque Converter Assembly Removal .

    • Pump shaft seal for leaks--Refer to Oil Pump Drive Shaft Assemble .

    • Spacer plate gaskets torn or leaking--Refer to Control Valve Body and Spacer Plate Assemble .

    • Pressure regulator valve stuck--Refer to Control Valve Body Disassemble .

    • Abnormally high or low line pressure--Refer to Line Pressure Check .
  3. Using the scan tool, clear the DTC. If DTC P0752 or P0757 is set, drive the vehicle to ensure the TCM commands 1st, 2nd, 3rd, and 4th gears. The ratios should match the commanded gear for all gears. Refer to Shift Solenoid Valve State and Gear Ratio .
    ⇒If the gear ratios do not match the commanded gear, inspect the following and repair or replace as necessary:
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