'88 Corvette transmission w/140,000 miles burn out sitting at shop w/o running?

How was the transmission working when you parked it? How have you driven the car? Drive it like you stole it, or going to church on Sunday with grandma in the passenger seat? Have you ever serviced the transmission? $1700 is not a lot of work, as most of it would be labor. What did he do to it? Were seals bad, pumps not working, or was it just a cleanup and tuneup with adjustments? If he did the work without asking you, you may have a recourse. Did you tell him to go over the car and fix everything, giving him a blank check, you may be stuck with a repair bill. Did he tell you what was done? A replacement tranny is way more expensive than $1700. Around 3Xs or more for a rebuild or new transmission. My question is, how can a transmission "burn out" when it is not being used? Did his test drive do damage to the tranny? Lots of questions here before passing any judgement on Bubba.

He replaced transmission R & R Remove & replace transmission & Torque converter, Flush coolant lines from transmission to radiator, 3 yr. warranty

I stand corrected. On line rebuilt 1988 Corvette transmissions can be had for around $750 (1 yr. w) to $1100 (3 yr. w) so if he is offering three years on the job, sound good. Bubba did good.