James, I would suggest you contact a tranny shop in your area. Any tranny shop worth its salt will have one laying around. You dont need one that works, just one that doesn't have a cracked case, for measuring purposes. I am sure they will lend you one.
IF the tranny shop can't help you, contact a wrecking yard. If not them, contact a tow company.
I am planning the same thing. I dont wnat ot purchase a new one, and get the warranty clock ticking, until I am ready to use it.
Tom