Do you think there is no problem with the tranny when it reverses ok?

Checked fluid level, ok. Also found no leaks.

Before it finally gave up (as I assume), the tranny slips on 3rd gear. I'll have to put it on D2 to move the gear back in place.

I think the tranny overheated when I played around the gears (d2, d1, d2, d1) coz its really having a hard time to make the car move during a very steep up and down zigzag road.

Now, it will move on D2 initially, and wont move after a full stop. Ill have to give it a rest for a couple of mins to make it move again.