i have a 2000 monte carlo ls with the 4t65e transmission, and when i accelerate from a complete stop the front end of the car violently shakes (as if the tcs is not engaging correctly or engine mounts are gone). but when i put the car into 1st gear (as if driving a manual) it does not shake at all... i can floor the accelerator and it will not shake... quite confused at this point... i dont know if i need a new or rebuilt transmission, or something as a sensor of some sort. thanks

 

Check your motor mounts, that could be the issue

Is the check engine light on?

It could be a connection issue with the shifter, possibly

Did you check the transmission fluid?

 

the only diff i can think between the D/OD position and the 1st gear position is possibly that the TCC isnt locking. try to have it in D or OD and have your foot lightly on the brake. no pressure but enough to activate the brake light. this trips the brake switch and keeps the Tq converter unlocked. if there isnt the stumble then it is something with the Tq converter lock up that is causing the issue...

did you have any PCM's or tuning done with the car? if so my money is that the trany settings are causing it. If not, another possibility could be engine mounts. upper mounts i would check as they are easy but the lower trany mount may be at fault.

 

well the check engine light is not on, and while im driving i also dont have overdrive ( i dont think? it stays at 2000 rpm while driving on the highway, dont know if this is normal) there is no d/od selection in my car... ummm... maybe the shifter connection, the tranny fluid i check every week just to be sure lol. no tuning done to the car, all i have done is put a CAI and a magnaflow muffler on her. ill try the brake switch thing you told me about when i leave work today. thanks for the help guys, i want to put urethane upper motor mounts on her but there kind of expensive and hard to find, even just urethane suspension is hard to find for my car...

 

so i did the accelerate with foot on brake and it does make it somewhat dissapear, so its the torque converter? doesnt seem to expensive!!!