Moneypit53,
The Chevrolet Tandon axle "Power Divider" used from 1956 thru 1959 incorporates an Auxiliary Transmission. The unit is mounted to the rear of the Main Transmission and ahead of the rears. One lever in the cab allows the operator to select one rear axle or both (Power Divider). The built in Aux trans is shifted with a second stick providing 3 ranges to select from (Low-Low, Low & Direct). My Chevrolet literature has it listed as a "Combined Power Divider & Auxiliary Transmission".
My literature also list the make/model as Truckstell Model 500. I don't know when the name was dropped but it's still used in my 1959 literature.
Sorry if there was any confusion.
Mike B
