Nissan Repair: Transmission Conrol Unit 1995 Nissan Altima, transmission control module, nissan altima

Question
I have a 1995 Nissan Altima GXE 2.4L. About a week ago the check engine light came on and the transmission would not go into reverse, first or second - third and higher ran fine.  I pulled the pan  and flushed the trans fluid, installed a new filter and gasket. Now the transmission goes into reverse, first, second and third, but not higher.  Codes pulled as P0731, P0732, and P0734.  

The parts store said I might need a transmission control module.  Is this the same as the ECU that is found in front of the center console inside the kick plate from the passenger side.  Or are they two different items?  The part in front of the center consol is a square box with Nissan number JA18C50 EF8 5404 on it with a big bold 6R also.  

When I talked with a Nissan dealer they gave me a Nissan part of 31-036-4-E800 for a transmission control module.  Just not sure I am talking the same parts or numbers?  Any help and direction would be appreciated.

Answer
Hi Tom -

A P0734 code is a fourth gear function code. Service manual states. That code is set when the trans cannot be shifted into 4th gear even though the electrical circuit is good. Probable causes shift solenoid A solenoid B line pressure Clutch pack wear or a hydraulic pressure leak that controls the 4th clutch. You probably do not have a Transmission control module problem. When the trans was changed did you also check the cooling lines? Bits and pieces of the transmission could have been lodged in the oil cooler in the radiator and that can ruin a transmission. You can also replace the in radiator cooler with a aftermarket tranny cooler.

If the TCM is defective, it is located between the front seats in the console.

Hope this helps -
aloha
Calvin