Mechanics

TRANSMISSION UNEXPECTEDLY DOWN SHIFTS

1994 Mitsubishi Expo

Transmission problem
1994 Mitsubishi Expo 4 cyl Two Wheel Drive Automatic 194632 miles

First, I think that my vehicle is the 2 wheel drive model, but it might be all wheel drive.

My 94 Expo's transmission will decide about every four to six months to randomly down shift, sending my RPMs through the roof. When this occurs, it feels like my brakes are being applied, even though my foot is always on the gas when the down shift occurs, and I can hear a squeak as if I were trying to 'peel out' of a parking lot.
It occurs between the speeds of 25-35 mph. Last February, I lost 5th gear completely. I have taken it to a repair shop and they said that they could test the electronics, but that minimum cost to fix the thing was going to be $1,400.00. I parked the car to save up the cash to fix it, and when I got back into the thing to drive it to the shop, it was working perfectly.

So, do you have any ideas as to what could be causing the change in transmission performance?
Avatar
EGuest
July 23, 2009.




Honestly, this is a tough one to diagnose without scanning the computer for codes. If I had to guess, I would say there is a problem with the vehicle speed sensor (VSS). This sensor sends a signal to the computer to tell it when it's time to shift. Again, without scanning it, this is an educated opinion. THe scan will identify it I'm correct.

I find it interesting that they said the minimum to fix it will be 1400 without knowing what is wrong. Has the check engine light ever come on?



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