Hi Steve, the T87D is the HD 3 spd. Synchronized in gears 2 and 3. Spur gears in 1 and R. Not a bad trans for daily driving behind a flathead. That's what I'm using in my daily 48.
It rugged - bulletproof, even. I've been trying to wear this one out so I can go with on OD but it still looks like new inside after 4 years of daily use. (I just had the top off the other day) Parts are available from a variety of suppliers including Sacramento Vintage Ford.
Was your's in an industrial application? Mine has a driveshaft yoke that is attached to the output shaft.