You might try putting a spacer behind the seal to move the contact point with the torus hub to a slightly different position. Even 1/8" or so would be enough to get onto a fresh sealing surface. Check with FATSCO transmission parts to see if they have shifter linkage- - - -they specialize in obsolete automatic transmission parts.

http://www.fatsco.com/index.htm

I've done business with them for several years, and once you get past the "Noo Yawk" attitude case, they're good people!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!