Just go to the Partshopper link at the top of the page. Find the Steeda Tri-Ax T5/T45 or 3650 shifter, click on the more info link and it will tell you how to find out which tranny you hage.
I heard all 2001 Mustang GT's produced before 9/01 have T-45
trannsmission's and if it's made 9/01 or after you have a T-3650
trannsmissions. The Steeda tri-ax shifter for the t-45 and t-3650
are two different part numbers so,two different shifter if you get a
Steeda Tri-ax make sure you order the correct part number.