tranny problems

[aquapool]

1990 e34 535i. Automatic transmission is having shifting problems. Acts as if the kickdown switch underneath the gas pedal is on. overdrive will only go to 3rd, and in third it only shifts to second (once or twice a week). I replaced the switch under the pedal but no luck. reverse is starting to take a day off every now and then. once a week it will not engage. My question is does this sound like a sensor or computer problem since it is so spuratic. Or does it sound mechanical (should I start looking for a used tranny?) Any help is much appreciated.

[fkong777]

I'm no tranny expert but I would reset the TCU and change the fluid to see if it helps.

[aquapool]

I'm no tranny expert but I would reset the TCU and change the fluid to see if it helps.

transmission just serviced 2 months ago. this is probably a dumb question but how do you reset the TCU??

[fkong777]

transmission just serviced 2 months ago. this is probably a dumb question but how do you reset the TCU??

unplug the TCU or disconnect your battery for a couple hours.

I wonder if your tech "serviced" it right.. your car needs to be running on idle and then pump ATF in until it overflows.. you are suppose to have the A/C running too to give it a little load.