lock in converter only engages once in a blue moon & i do alot of highway driving. is it internal or a solinoid or sensor. also the temp gauge runs on the cool side, may a thermostate be causing other issues??? has 3.0 with 200k.

 

There could be a link between a defective thermostat and converter issue.

The converter will lock out if the coolant temp is too cold as when the engine is warming up.

Note: The temp gauge on the dash and the trans computer that controls the converter use different coolant temp sensors.

Suggest checking the coolant system to determine if the coolant really is too cool or it is a temp gauge issue.

If the coolant is too cool and this is fixed, the trans issue may go away.