Hello all!

I have a 1999 Mazda Protégé that I recently bought used and as is. It is automatic with 148k miles. Recently, it has acquired a problem with shifting. When I start the vehicle up to drive it, it will drive and shift from 1st to 2nd gear, but once I come to my first stop and go to drive again it stays in 1st gear will not shift into the next gear. Within minutes after this happens, the O/D light flashes. It continues to flash whether you are moving or at a stop and in park. If you go to shift the vehicle into D or R while this O/D light is flashing it shifts hard and abrupt. If you turn the vehicle completely off and start it right back up the O/D light is off and when shifting from D to R is shifts smoothly, mind this is all while I am sitting still in my driveway. I did pull the pan off and drain the fluid in there, I know the torque converter still holds a few quarts so wasn't able to get to that. The fluid was very dark and old, but there were no metal shavings. I replaced the transmission filter and gasket and cleaned the pan out as it was nasty. I also replaced the vehicle speed sensor as I have heard those can cause issues if they are bad, but still no luck and no change in the driveability. The new transmission fluid does not smell burnt. It had a check engine light code at one point that said P0751 I believe. Anybody out there who has first hand experience with this problem or any recommendations would be greatly appreciated. I have a spare transmission laying around, but I prefer to not swap them out as I am holding on to that one for my lime green 00' Protégé. Thanks guys

 

Well, I don't have first hand experience.

That out of the way: you have a bad shift solenoid or a sticking valve. The code would point to the shift solenoid.

You need to fix this because the clunky shifts can do serious damage.