hey all, i have an 03 with about 105k on it. i bought last summer and completed the entire high mileage service on it and replaced the headgasket due to some leakage of coolant near the drivers side firewall.

the problem i ran into this winter was the torque converter was locking up when i first shifted into drive or reverse from a cold start. the tranny would lock up, jerk the car forward, and stall the engine. if i shifted into neutral when it locked up the rpm's would come back up and the engine would recover.

this only happens below about 25f ambient temp when the engine is cold, when the engine is warm it works perfectly.

is this a fluid viscosity problem? ( i used valvoline high mileage dex in the red bottle and a bottle of lucas tranny additive)

or is this a fluid volume problem, either too low or too high?

or is it a problem within the tranny that i will see continually getting worse?

thanks!

 

Torque converter lockup is accomplished by the Trans ECU commanding the solenoid valve in the trans to engage the lockup clutch in the trans. So it could be any of the 3 (and the wires in between). I doubt the fluid has anything to do with it. Since it's temperature dependent it could be any of the 3 (I know that's not a lot of help), I can envision temperature affecting a circuit board as well as the cold temp affecting both the clutch and the solenoid. Running the engine warms up the trans and the heater warms up the interior. Maybe a way to narrow it down would be when it is this cold, put a plug in electric space heater inside the car (passenger front footwell) and warm up the interior. Then if the trans doesn't lockup, it narrows it to the ECU, if it doesn't then I would suspect an internal trans problem. HTH