I have a 1991 Mitsubishi Galant - automatic transmission. To summarize my problem, I'll just say I bought the car at an auction, drove it about an hour to my sister's house and parked it overnight. The next morning, the car wouldn't shift out of low gear (reverse was fine). Brother-in-law checked the fluid and it was empty, but there were no leaks and haven't been any after we filled it. My father changed the filter with no change.
Since then, it has taken shifting "spells", but hasn't been consistent. In other words, there are days when it will shift into all the gears (slow start from take-off, but shifts fine after that with good speed and good downshifting on curves).
It has a transmission control module (electronic shifting), so he pulled the fuse to it to see what it would do. With the fuse still in, the car sticks in low gear (still has reverse), but without the fuse, the car sticks in high gear (still has reverse). Am I looking at having to buy a new module or am I way off base here with what the problem may be?
I will say again that when it does decide to shift, it runs great so I don't believe there is anything wrong with the transmission. A transmission "expert" told my dad that the transmission computers are designed to lock the transmission in low gear in case something happens so you can get the car off the road. Could the lack of fluid have caused damage to that unit?
I hope I gave enough information, but if you have a question, I'll do my best to answer. Please be gentle and Thanks!!