94 ATX won't shift out of first

[GreenBird]

Without me or my dad looking at it, my mom got a 94 ATX. When te car is cold, if shifts fine, but once it warms up it won't even shift out of 1st.

PO said it did it before and a fluid change fixed the problem. Well it didn't this time.

 

[SolidState]

bad shift solenoid?

I know little about this stuff, but maybe you could try pulling the codes...

 

[GreenBird]

No codes.

 

[Mr Anonymous]

Where it only seems to happen hot, a possibility might be a restriction/blockage in the ATF cooler lines, resulting in the oil overheating/boiling. Next time it happens, feel the lines on both sides of the cooler (in front of the A/C condenser, at the bottom, about 4" wide x 22" long). If both lines are cold, or one is super hot and the other cold, then you have a restriction some place.