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RPM per MPH 2004 Grand Prix GTP (Resolved)

T

tquinn

New member
My daughter has a Grand Prix 2004 GTP, and we just had a rebuilt transmission installed at about 122,000 miles. As I drove it home, it seemed like the engine was running a little higher RPM for the speed, which might mean it was either not going into 4th gear, or it was but the torque converter lock-up clutch is not engaging.

If any of you have a GTP of this model year, could you please check what the engine RPM is at 60 MPH after the car reaches that steady speed, and report back here? On her car it is about 1,700 rpm, which seems faster than normal, but I haven't driven the car regularly for a long time.

To make this comparison valid, you must be driving the supercharged GTP, because that has the 4T65E-HD transmission. That transmission has a different ratio than those used in other models of the Grand Prix that year.

I realize that another possibility might be if they had gotten the wrong transmission installed, but that would have dropped the rpm, not raised it. I also discussed that with the owner of the shop before he did the exchange, who understood the importance of getting the right tranny in. Plus if it had been wrong, I'd be getting a check engine light by now, as the wrong tranny sets off alarms in the ECM, and that hasn't happened.


Thanks in advance for your help,

Terry
 
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Re: RPM per MPH 2004 Grand Prix GTP

shes running perfect, same tranny, i run about 1800 ish. if you were at 2400 then you'd have no 4 th or a bad tc issue.
 
Re: RPM per MPH 2004 Grand Prix GTP

tquinn said:
My daughter has a Grand Prix 2004 GTP, and we just had a rebuilt transmission installed at about 122,000 miles. As I drove it home, it seemed like the engine was running a little higher RPM for the speed, which might mean it was either not going into 4th gear, or it was but the torque converter lock-up clutch is not engaging.

If any of you have a GTP of this model year, could you please check what the engine RPM is at 60 MPH after the car reaches that steady speed, and report back here? On her car it is about 1,700 rpm, which seems faster than normal, but I haven't driven the car regularly for a long time.

To make this comparison valid, you must be driving the supercharged GTP, because that has the 4T65E-HD transmission. That transmission has a different ratio than those used in other models of the Grand Prix that year.

I realize that another possibility might be if they had gotten the wrong transmission installed, but that would have dropped the rpm, not raised it. I also discussed that with the owner of the shop before he did the exchange, who understood the importance of getting the right tranny in. Plus if it had been wrong, I'd be getting a check engine light by now, as the wrong tranny sets off alarms in the ECM, and that hasn't happened.


Thanks in advance for your help,

Terry
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Does your daughters car have Tap shifters on the steering wheel?
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Re: RPM per MPH 2004 Grand Prix GTP

I plotted the speed vs rpm of everyone's answers here, and 1,700 rpm at 60 mph fits the curve perfectly. So there is nothing wrong with my daughter's car.

I probably got concerned because the tranny had just been replaced and I was listening for problems. Plus I drive a '02 Corvette Z06, and its 0.6:1 overdrive top gear would make me more used to lower engine speeds, something like 1,500 at 60.

Thanks for all the help!

Terry
 


Re: RPM per MPH 2004 Grand Prix GTP

This site is made with a whole different software that doesn't have that, or atleast this version anyway. We don't really have an owner anymore but that is a long story not worth getting into.

You can use your first post, then advanced edit to change the thread title if you wish.
 
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