Q: How do I tell the difference between a Tremec 3650 and a T-5 transmission in my Mustang?
A: In 2001, Ford used two different manual transmissions in that year’s SN-95 Mustang. The easiest way to tell them apart is to look for the drain plug.
The T-5 (T-45) transmission has the drain plug on the passenger side of the transmission case.
The TR3650 transmission has the drain plug on the bottom of the transmission case, pointing straight down toward the ground.
Learn more about identifying automotive transmission here, including this visual chart from Holley showcasing manual transmissions specifically.