Generally no change for break-in. First change is typically at 20k miles, but there is nothing in the FSM about service intervals. Some manufacturers are filling with high quality synthetics and calling it good for the life of the vehicle. That's not to say you might be able to extend the service life well beyond 250,000 miles by changing it, just that the factories have determined they will get acceptable service life with the original lubricant.
Given the triple cone synchros for first and second, I'd say they expect this gearbox to last a very long time without issues.
FWIW, it holds 2.5 liters of 75w-90 API GL-4 or GL-5 gear lube. I expect I'll be putting Red Line MTL in it when the 20,000 mile mark rolls around. MTL works great in transaxles, it was designed for them.
Sort of. Toyco is constantly changing part numbers for common things like oil filters, so I can understand why they don't have part numbers in the manual. Imagine the product liability if they list a part number, then supercede it with something else and the customer insists the engine seized because he didn't get the oil filter specified in the manual, even though his dumb @ss failed to tighten the drain plug and all the oil drained out.
Toyco is VERY liability conscious. You have no idea what I had to go through to get a service manual for my Getrag gearbox in my Supra. If I hadn't got some special assistance from someone in Toyco management, I'd still be trying to get that book. Toyota Motors USA actually called me on the phone to tell me they were not able to get me the manual for liability reasons. So, no part numbers does not surprise me at all.
Speaking of which...I'm picking up my new tC on Monday...is there a proper break-in procedure listed in the manual? This is my first brand new car (it's got 11 miles on the odometer), so I want to do things the right way. Thanks for the help in advance.