My 1995 dodge Dakota intermittently will not engage the torque converter or overdrive. It is worst on hot humid days and on rough roads. It is very low mileage and has been maintained very well. My mechanic is baffled and I am at the end of my rope.

 

The lockup and overdrive solenoids in the Valve Body have one thing in common. A 12VDC source to the center pin of the 3-pin connector. If you are intermittently losing both, especially on bumpy roads, you have a loose/corroded connector or a hot to that connector.

Reference this thread for the harness location and pinout diagram

https://dodgeforum.com/forum/1st-gen...se-help-5.html

 

My mechanic fixed the moisture and corrosion problems now it won't engage tcc solenoid or od at ambient temperatures above 80 degrees Fahrenheit what next

 

Same problem. Thermal expansion is loosening the connection to the 12VDC source. Use the diagram I linked and trace the VDC through the harness. That's assuming you are losing both. If just one or the other, then you're losing the ground to that solenoid only.