I have driven a number of U-Haul trucks for various reasons (and most were IDI's, with a couple of 460's in there)...and, seeing how wonderfully they're maintained, I go out of my way to NOT rent from them now. I wouldn't even consider purchasing one unless the body was immaculate and I didn't care what condition the drivetrain, electrical, etc. were in. I'm pretty sure that U-Haul doesn't let trucks go until they're badly worn-out.
Too bad; that looks like a nice truck from the pictures, and the dump bed's cool
but U-Haul's version of fleet maintenance scares me! I wonder how many times the odometer rolled over before your friend got the truck? Also, other than the tranny, what has been done to the truck since it was liberated from U-Haul's grubby little hands?
If it weren't for the dump bed, I would think that $2000 was fair (would have said $1000 to $1500 except for the new tranny), but I don't know what it's worth with the dump bed in place...