Those transmissions show up on Ebay occasionally- - - -search "Brown-Lipe" or "auxiliary transmission". Ignore the ones for the big rigs like Peterbilt, Kenworth, etc. You'll be looking for the medium duty trucks.
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!