My mechanic said if my transmission dies I will need a new, not rebuilt one. on 2004 Mazda MPV

He says no one is able to rebuild a Mazda MPV transmission properly so they just buy new one from the dealer and install it. I got a quote of $4500 which seems exhorbitant.
I love this van but if this is an accurate repair quote I would rather sell it and start again. There is nothing wrong w/ the car now but it has 176.000 miles on it and I am tryig to make an informed decision as to sell or not.

Asked by for the 2004 Mazda MPV
alot of people r/b them but some repl thats your choice. at times some parts are no longer available but most are. call aamco and get price and that will tell you the answer