300ZX auto gearbox wont change out of 1st gear

[greyham]

I have a 93 300zx, it was driving fine except that i used to have to ease off the accelerator to get it to change from 2nd to 3rd gear. It is now refusing to change out of 1st gear at all. I suspect it requires a new gearbox, but i have heard that other people have had this problem and that it was an ecu or something.I believe the car has a self diagnostic system built into it (bleep codes) does anyone know how to test it electronicaly before i change the box.

Graham

[s13sr20chris]

i dont know offhand where the tcu is located but if you are able to find it and unplug it then it will put you in failsafe mode. that will give you 3rd gear and reverse only. if you have that then it is an electrical prob. if you do that and are still stuck in first then you need a trans.