Subject: 1992 Diamante Trans stuck in 2nd gear
Question:

I owned 1992 Diamante since it had 0 miles(1st Owner). Car has about 120,000 mile on it.
Recently I have had front right and left axles replaced. Right after that I noticed trans fluid on my garage floor. I took the car back to the place I had the axle work done and he pointed out that the seals are leaking which he replaced. There is no more fluid leak but now I am noticing that transmission is stuck in 2nd gear. My mechenic also said the same thing that the trans is stuck in 2nd gear ... no overdrive either. I do have reverse but when i put it in D(drive), 1 or 2nd...it stays in 2nd gear and i have no initial pick up from stop. When car is put in reverse, i feel a big thud. He says I need a transmission rebuilt which cost about $1500. I have reset the computer by removeing -ve terminal of the battery per one mechenic's advice. No help there... Also after doing all these I took my car to the Mitsubishi dealer to have code retrived, and his analysis is ... that code reader can not communicate with the TCU(Trans Control Unit). Any help is appreciated !!!
Thanks
DT
Answer: DT,
The problem could very well be eletrical. If the Mitsu mechanic could not get a signal from the TCU, than that would indicate to me that either an eletrical harness is loose on the TCU, or the TCU itself is malfunctioning. There are cases on early Mitsubishis having computer problems with their ECU (engine control unit). You can read this article for further information:
http://www.90gsx.com/eclipse/cap/caps.htm

I would have the TCU pulled and at least visually inspected for damage, and even have it sent out to a ECU/TCU internal diagnostic facility. I mention a few of them on the website I provided. But if the TCU appears to be fine, I would question the mechanic that replaced the axles and seals for any damaged they might have caused or possible eletrical wires they may have disturbed while perform the repairs.
Good luck!