elgonza69

i've been having a little bit of a headache trying to figure out whats the problem that i'm having with my '96 z28 tranny. don't know the model of the trans, but what i can tell you is that it doesn't have a 1st gear in the shifter (2,D,OD,N,R,P). the problem is that sometimes the lockup activates at 45 mph and sometimes it doesn't activate at all. replaced the trans filter, fluid, and still the problem persists. tried different strategies of testing it and if i let the car heat up to its operating temp, it works perfectly, but if i roll out without letting it reach the normal temp, it doesn't work. what could be the problem??? would really appreciate your help.

97pontta

Maybe some one more familiar with the A4 can chime in but from what I can remember the engine has to meet cretin parameters before the PCM tells the transmission to lock the TCC (torque converter clutch). I know TPS voltage, vehicle speed, engine temp, and any engine misfires will control when the TCC locks up, if at all. When I had my auto I remember it being common for the TCC not to lock up until the car entered closed loop. You may want to check the coolant temp sensor and make sure it is working properly. I live in the midwest and in the winter my car doesn't get much above 170 while driving, and only about 185 while setting but I have a 160 thermostat.

Make sure the engine is running well also, any engine misfires will cause the TCC to unlock or not lock at all. And if you have access or know anyone with access to a Tech 2, or similar device, you can command the TCC to lock. If it doesn't always lock when commanded it could be a bad TCC solenoid.

Performabuilt

You must be at normal operating temp other wise the PCM disables lockup until you are

elgonza69

sorry to ask (i'm new at this) but what is the closed loop?

97pontta

Closed loop is the mode your PCM puts the engine in once the proper operating tempature is reached. If you start your car cold the PCM is in open loop until the engine warms, the car will not function exactly the same in open loop as it does in closed loop.

elgonza69

thanx for all your help. As a new Camaro owner there's a lot to learn about them. They seem simple on the outside but the're a little more complicated than I thought.