2001 Grand Prix GT RPM's at 65 MPH

[BNaylor]

Are you sure 4th (OD) gear is even engaging? In order for me to rev 3000 rpm @ 65 mph I have to keep it in 3rd gear which will obviously inhibit TCC lockup on top of that. In that scenario I see around 2500 rpms by keeping it in D3.

I wonder if you have a mechanical issue like a bad 4th clutch shaft which is common where the splines strip due to poor material. Not hardened.

[chris peter]

I just tried driving in 3 instead of D. It shifts 3 times which would be 4th gear when in 3 does that make sense? That last shift it drops 500 RPM but if I shift into 2 it drop way down push it up to three and it shifts twice. Something doesn't seem right.

[troy1]

I'm pretty sure your missing 4th 3K @65 is 3rd gear. the double shift you see/fell is 3rd then TCC engagement.

[chris peter]

That makes sense, does this mean trans rebuild time.

[richamos]

Hello,

I am encountering the same problem with my 2001 Chevy Monte Carlo SS. I am running at about 3250rpm at 74mph. My GM Tech 2 says it is in 4th gear, but when I shift it down to 3rd gear there is no change. I noticed the TFT sensor readings are way off. My transmission should be running at about the same temp as the engine and probably higher. I drove the car over 10 miles tonight while monitoring the TFT with the Tech 2 and the temperature never exceeded 150 deg f. I also noticed the TCC only operated at about 24%. I am going to check out the wiring going to the transmission, if that is ok then I will drop the pan and check the wiring and if that is ok I will replace the TFT sensor and go from there. I will post my findings.

Rich

[BNaylor]

Originally Posted by richamos

Hello,

I am encountering the same problem with my 2001 Chevy Monte Carlo SS. I am running at about 3250rpm at 74mph. My GM Tech 2 says it is in 4th gear, but when I shift it down to 3rd gear there is no change. I noticed the TFT sensor readings are way off. My transmission should be running at about the same temp as the engine and probably higher. I drove the car over 10 miles tonight while monitoring the TFT with the Tech 2 and the temperature never exceeded 150 deg f. I also noticed the TCC only operated at about 24%. I am going to check out the wiring going to the transmission, if that is ok then I will drop the pan and check the wiring and if that is ok I will replace the TFT sensor and go from there. I will post my findings.

Rich

Obviously it is missing 4th - OD. Sometimes 4th gear engagement will be affected by the weather conditions. How cold is it in your area? And no transmission oil cooler installed?

Drop what pan? You are aware the TFT sensor and the solenoids are under the side cover assembly (driver's side) so it is a bigger job. Just want to make sure you realize that.

[speeddemon29]

Just curious if anyone was able to determine the cause of this problem, my 1999 grand prix just started doing the exact same thing!

[ljgc77]

I have a 2001 pontiac grand prix and my car is experiencing the same problem. I am getting really bad gas mileage. My check engine light is on because of the EGR. Could this be contribute to the problem?

[LMP]

60 mph is near 2000 rpm in 4th gear with TCC applied.
I assume you miss 4th gear and TCC......and probably the cruise control is inoperative too.
Most probable cause: failed throttle position sensor.
Veryfy this link... www.avigex.ca/xport/dtc21.jpg .(DTC# is from OBD1 but same with OBD2 #P0122/123/124)
Of course reading the codes would confirm.

[chris peter]

I never fixed mine it still running with only 3 gears. The engine runs great I just never spent the $1000+ to replace the trans. I use the car in the city most of the time now. It's been over 4 years now.

[Tech II]

Ljc77, you are jumping into an old thread......should start your own.....

Experiencing the same problem?

Exactly what is your problem? State all if more than one......

Does your car shift into all 4 gears? Does the TCC engage? What are your rpms at 60mph on the highway?

Is the EGR setting the only code? If yes, what is that code number? If not, what are the other codes?

You say your gas mileage is bad......approx. what is the MPG? What was it previously?

Pull the vac line off of the fuel pressure regulator......seeing/smelling fuel in the vac line?