1992 E4OD
I was reading in the owners Manual trying to find an answer to this question but no luck.
My question is it alright to shift between Drive 'D' and 'D2' or 'D1' while driving and in motion?

If so any specific proper way? I would assume while coasting and at any speed is fine?

I do have an external trans cooler but would frequent switching between 'D' and say 'D2' create excess heat?

Any info provided would be great, thanks.