Engine Braking and A/T temps

[4Mogger]

Clearly climbing a grade will cause an A/T to heat up, particularly if you allow it to shift around and "hunt" for a gear. But will descending a long grade in a single gear, no shifting, cause the transmission temp to rise?

[SolidAxleDurango]

Yes. Your transmission generates heat any time the torque converter is unlocked. It doing this via "shear".

~Generally~ most trannys only lockup in direct or OD... But that is a very sweeping statement. To find out you'd be best to check a FSM. Even different program modes may have different lock up characteristics.