International used a lot of Browne/Lipe auxillary transmissions with a 5 speed main transmission. Saw a lot of them in dump trucks. Having the extra low gears helped start the load moving when in off road conditions.
So did Autocar, Mack, Brown and Corbit back in the 50s, most were 3 spd.
One company had a 46 Chev. 270 GMC engine, 4 spd main, 3spd B&L, full air brakes, ran from Charl to Akron O.