02 Transmission Problem

[DJS4R]

i have a 02 sr5 4x4 3.4L and i need some advice, it starts fine but when i put it in D or R it just dies some tell me the torque converter is locked and a mechanic said (over the phone) it sounds like the overdrive gear broke and had a few in his shop and he quoted me $2800 for a rebuild parts and labor. i dropped the filter and there's a lot of metal pieces. i have a extra trans but im trying to find out if it is compatible im going to the dealer today and see if i can give them the serial # to see if it is.