Subject: Mitsubishi Transmission in 1993 Diamante
Question: I have just purchased a 1993 Diamante station wagon with 56,000 miles on it. It is the 3.0L motor which, except for needing high test gas, appears to run excellent. However, when the car is cold, the transmission slips. I took it to the dealer and they replaced the transmission fluid because they said it looked dirty. Funny because I had just had it done not 200 miles earlier. When I then explained that the motor would rev before the gear would engage when coming to a rolling stop, they cleaned the throttle body. It did not cure the problem. I have seen that there are some technical updates on this problem, but I cannot find them anywhere. The dealer says the transmission just does this and everything is fine. What do you think?
Answer: Terry,
The problem the dealership indicated with the dirty transmission fluid could be true. Even though you changed the fluid only 200 miles ago, you may have not cleaned the filter (actually its just a screen). If that filter is not cleaned and the old fluid thoroughly flushed, it can make the new fluid look a little dirty.
The transmission issue you are experiencing is pretty typical of the older Diamantes. Most questions I receive from other Diamante owners deal with transmission problems. You may have a problem with your torque converter, but your mechanic may indeed be right. There probably is nothing seriously wrong. If you are unsatisfied with the answers the dealership is giving you, get a second opinion from a tranmission specialist shop. Your local garage mechanic will probably not have the correct tools or knowledge for your complex transmission.
Good luck!