I heard this about his vocal work for the ride, wonder if it's true:
"This was imparted to me by one of the show designers at a meeting at WDI. Just before Indy opened. Harrison Ford had originally agreed to voice the three Indy characters but would only do it on the condition that they not ask him to appear or do any recordings for the half-time Super Bowl show that year the ride opened, which did have a blatant promo for the new attraction. Well, as fate would have it, he was scheduled for a Saturday recording session, the studio was rented and ready to go. However, a low level idiot in marketing over at the studio, not aware of the agreement, sent a script to Mr. Ford of the Super Bowl show instead of the attraction script, the Wednesday before the scheduled recording. Incensed that the one simple request was not kept, he canceled just one day before on Friday."