transmission problem

HELLO ALL,
this is my first time on this forum.

I had a used transmission installed in my grand prix 2000 with the 3.8 and i am contuning to have problems with it shifting. when i first start driving, it shifts smooth and then after it warms up it begins to shift hard. my transmisson is 4t60e. i have disconected the battery for 24 hours to see if it would reseat the system and this has not fixed the problem. if anyone could give me some advise on what the problem could be, i would be greatly appreciated
thanks

Welcome to AF!!

Take the car to a tranny shop and have them scan it. They can test shift points and check the programming in the PCM to see if everything is working correctly. It is possible that the computer is malfunctioning and is causing your shifting problems but this is the only way to tell for certain.

my transmisson is 4t60e.

:confused:

Are you sure you have a 4T60E autotransaxle? Based on your year you should have a 4T65E GM RPO code M15. Check the SPID label on the back of the trunk lid. Big difference between the two transmissions since the fully electronic 4T65E uses a pressure control solenoid (PCS) to control line pressure and not a vacuum modulator both of which will affect shift quality.

:confused:

Are you sure you have a 4T60E autotransaxle? Based on your year you should have a 4T65E GM RPO code M15. Check the SPID label on the back of the trunk lid. Big difference between the two transmissions since the fully electronic 4T65E uses a pressure control solenoid (PCS) to control line pressure and not a vacuum modulator both of which will affect shift quality.

Im sorry you'r right, it is a 4t65e,
I tooked to the shop today,and after they put the computer scan,it come up with a code (improper gear ratio)
so, I guess ,I needed to take my car back to the mechanic and tell him that the transmission that he put in is not the right one,
anyway thank you for the help.

Thanks for clarifying. That is a common problem if you get another 4T65E autotransaxle installed that may be from another model GM car since many have that tranny. The final drive gearing ratios vary. One way to remedy the improper or undefined gear ratio DTC which should be P0730 is to have the GM dealer service department reflash the PCM module and they can adjust it accordingly with a Tech II scan tool. Until then that particular DTC will command maximum line pressure which will cause the hard and/or erratic shifting.

Thanks for clarifying. That is a common problem if you get another 4T65E autotransaxle installed that may be from another model GM car since many have that tranny. The final drive gearing ratios vary. One way to remedy the improper or undefined gear ratio DTC which should be P0730 is to have the GM dealer service department reflash the PCM module and they can adjust it accordingly with a Tech II scan tool. Until then that particular DTC will command maximum line pressure which will cause the hard and/or erratic shifting.


So did you think the with only having the dealer to reflash the PCM module will taker this problem, without taking the tranny out and changed the internal gear ratio.

Do you know what make or model GM car the tranny came out of?

Send the member that posted this thread at the link below a PM message and see if the reflash did, in fact, resolve his issue.

Click here (http://www.automotiveforums.com/vbulletin/showthread.php?t=889728&highlight=reflash+gear)

I know of one other member here at Grand Prix that addressed a similar issue with the undefined or incorrect gear ratio but the PCM reflash did not work for him. But the tranny was confirmed to be his original and not a replacement. Plus he had other issues like secondary ignition. Good luck!