For most of us in the hobby its common knowledge to have more then one vehicles, multiples of various parts or assemblies. This has come true with my project as it turns out having more then one transmission has saved me as the original transmission turns out was cracked running almost all the way around the case, nearly split in 2.
The second trans was holding oil and shifted through all the gears, what I didn't do was open it up to inspect the condition of the gears, turn out "Grind it until you Find it" was standard operating procedure for the previous operator. This lead to pulling the internals out of the cracked housing and installing into the good one.
https://youtu.be/9b4WjDeWMPE?si=Gy6wABokdtnYIMow