I have a 1994 Trans Am basically stock engine except for a Borla cat back exhaust & Moroso cold air intake. The car has 40700 original miles. The auto transmission shifts hard into 2nd gear almost as if someone hit my car in the rear, otherwise it runs fine. I've had to replace the tranny mount. I have no idea what is causing this. Anyone experience anything similar and what was the remedy?

 

Well if you have no codes and you have not installed a shift kit I would check the 1-2 accumulator

 

Does it do it all the time or only after it gets warmed up? Do you ever get codes? maybe your light is out because it sounds like it should me throwing a P1870 code which should make you light come on. How long have you owned the car? Maybe someone put a B&M shiftplus on it which makes the trans think its making much more vacuum then it is causing a really hard shift, you could do this with a simple resistor on the ecu as well. Without knowing all that info its a little tough to diagnose. Good luck.

 

I am the original owner, (bought it new Sept, 1993) it happens all the time (warm or cold) The service engine soon light works. I recently checked it, no current codes, but there was a "stored" code. I'll check it tonight when I get home & let you know what the code is. There is no shift kit. I have changed the fluid once a year for about the last 5 years when I got a TCI aluminum pan with a drain plug. The car has never gone more than 2 years, since new without a tranny fluid change. The filter has been changed 3 times since new.

 

No Current Codes

History Code: "73 Force motor current"

Per GM Service Manual: DTC 73 Pressure Control Solenoid Circuit (current error). DTC 73 will set when: The return amperage varies greater than 0.16 amp from the commanded amperage for at least one second and no DTC 75 stored. ACTION TAKEN (PCM WILL DEFAULT TO): Full line pressure will be applied causing HARSH SHIFTS. DTC 73 will be stored in the PCM memory but will NOT turn "ON" the Malfunction Indicator Lamp.
DIAGNOSTIC AIDS: Check for poor connections at the PCM and at transmission connector.
Well I'll be checking those connections this Saturday, I'll let you know if its that simple.

 

Make sure it's not a history code. Most trans codes don't turn on the SES (as your description stated for DTC 73).

 

The SES never turned on, the DTC 73 was listed as a "History Code." There were "no current codes."