First half of the model year was T-45. Feb 1, '01 was the date for the switch to the TR-3650. You can still find some later build dates with the T-45 though.
I am guessing the TR-3650 is a better tranny? I beleive I have the T-45 since my car was built in the first half. I am having problems with 4th gear popping out and grinding, so I neede to know what rebuild kit to buy.
If its a 3650, there is no rebuild kit as Ford still has the rights to the tranny and won't release anything, or something like that. A lot of people have had trouble with both the 45 and the 3650, but should you get lucky ahd get a good one, the 3650 should be the better tranny. I have no issues with my 3650 whatsoever. Ford is weird about when they actually put parts on during changes in production. I've seen early 01's with the 3650 and late 01's with the old style waterpump(even an 02 with the old waterpump).
I think the easiest way to tell is the drain plug. If its at an angle, its a T-45. The 3650 drain is like straight down. I may be mistaken or mixed up and there may be an easier way.
There is a sticker on the driver side doorjamb which has the code for the
transmission. My '01 has the 3650 trans but the car is not with me at the
moment (winter in New England) so I can't tell you off the top of my head
which code is which. Do a search through these forums, or the dealer should
be able to tell you.
I think the easiest way to tell is the drain plug. If its at an angle, its a T-45. The 3650 drain is like straight down. I may be mistaken or mixed up and there may be an easier way.