Here ya go for identifying a T5, see below info and links. Do not just rely on the casted numbers OR any “hang tags”. I just posted the below info a day or so ago in another T5 thread to help another VMF member.
As far as cost, I sold a WC T5 about 2 years ago that was completely disassembled, cleaned, damage free and had all new internals that needed reassembly for $250.00. A good working WC T5 from a Fox 5.0 (86-1995) is usually in the $400-$600 range (very fair pricing), depending on verification that it is in fact a true 5.0 WC T5 and that it’s not internally damaged.
Always check the external case and tail shaft housing to make sure there are no cracks.
First you have to determine which T5 you actually have OR what the Seller is selling... There’s a standard T5 and a World Class T5 (WC T5). There’s also the T5’s that were used in the Mustang SVO’s (other 2.3’s) and Ford’s Thunderbird Turbo Coupe.
Being in the Fox Body scene for over 20 years now, you have to be careful what you’re buying - because some folks like to pawn off a 2.3 T5 as being one from a 5.0 and claiming it to be a WC T5. You do not want to put a 2.3 T5 behind a V8....
To determine if you have a WC T5 or not, look at the front of the case where the output shaft is that the throw out bearing restrainer rides on. Near it, you need to look at the main bearing race that is pressed into the front of the case.
Non-WC will have or use a Torrenton bearing. Earlier Non-WC T5’s use gear oil.
A WC T5 will always have and use a Timken LM67010 bearing that depending on age and production era, appears in 2 different colors. From what I recall, the WC T5 race will have “Timken” stamped into the outer edge. WC T5’s will use ATF fluid, not gear oil!
This FIRST link has EXCELLENT info in not only identifying a T5, but also explains why you do not want to put a 4cyl 2.3 T5 behind a V8. The other sites I have linked are also very helpful:
The many different faces of the T5 - Modern Driveline
World-Class T5 Not all Borg Warner/TREMEC T5’s are the same. T5 Service Manual LINK The first T5 five speeds were introduced to market in 1980, in all things, an AMC Spirit/Concord. In 1983, T5’s were introduced to Fox body Mustangs and continued to be used in V-6 Mustangs until 2010. The T5 is…
www.moderndriveline.com
Identifying and Assembling a T5 5 Speed
Ford Mustang: Mustang Tech: Transmission and Drivetrain: Borg Warner T5 Transmission data