I have a 2000 Chevy Monte Carlo V6 3.4L 207 ci GAS MFI VIN E Type LA 1- 2 valve OHV FWD. Apparently had the transmission previously replaced for the transmission tag that I pulled out is a 2 in the year. I got a donor from a 2002 Pontiac Grand Prix V6 3.8 3800cc 231ci GAS MFI Supercharged VIN 1 Type L67 2 valve OHV FWD. I knew I went from a 4t65e to a 4t65e- HD and shorten the side axle. The trans that was in the monte had a external and the Grand Prix was internal not knowing it was a different transmission charged the wiring harness on the mode switch. Installed it but it wont go into any gears and there is a loud grinding noise. Its first transmission I am helping with and really want to learn how to rebuild transmissions I don't know what I did wrong or if I found the wrong donor..... uhu... please help.