just had engine swapped out, now tranny too hot (and no heat for inside)

[Alycone]

So, finally got my car back from the engine swap. Was purring like a kitten for 15mi, then heard some indigestion sounds and tranny temp spiked to max on gauge (somewhere north of 250). I was on freeway zipping along with no hill/traffic so nothing shouldve been stressing the tranny I'd think.

And I've got no heat for myself since I've got it back.

Any idea what might be wrong?