My son has a 94 z28 with an auto trans. It acts like the trans is slipping or the converter is slipping. But I really don't think it is a internal trans problem. The bad part is that I can't get my scanner to read the fault codes. It not linking up.

My gut felling there is a sensor that causing the problem but I don't know which one it would be or where to start.

If you stab the throttle it will hook up and even shift through all the gears. But if you just drive it normal it slips a lot in all the forward gears. Once you get over 40 mph it does better. Reverse is perfect and solid. I had plenty of worn out transmissions in the past and although this slippage is kind of the same it not the same. Also this problem popped up out of nowhere. Generally a worn out tranny give you some warning.

Can anyone give me a place to start?

 

sounds like the tcc is not locking up or the torque converter is going. whens the last time it was serviced?

 

Who knows on the service. Bought the car used and the is far from perfect. Where is the tcc located?

 

tcc is in the tranny. you should have the tranny serviced and checked. could also be tcc solonoid, you have a 4l60e transmission so the shift and coverter lockup is electronic.

 

I know he's not a sponsor here but you can use this guy http://www.lt1pcmtuning.com/

or get your own aldl cable http://www.aldlcable.com/ and download software. Your computer will tell you when the tcc is locking/unlocking

I'm not going to try and give you hope though. You may be looking at a rebuild

posted by a person who knows about getting the 4L60E rebuilt, then making more power with the engine, and then grenading the tranny again and rebuilding but with beefier parts

my slipping came slowly just like you describe. If you have plans for making more power, I suggest to pony up a few more $$$$ and make it stronger

 

Ditto on above, I used this guy on mine, evreythings Ok with the tune except the security dissable is not dissabled like I requested, but I cannot verify it. Next time I am getting the cable and software and doing it myself. This way you can see for yourself everything going on in the entire drivetrain. You will probably see that craby is correct, but you will know for sure.