Look at the end of your current tube: flat flange (Vactor and Vac-Con style), Bandlock or Ringlock. Match the connection and the diameter.
Aluminum or HDPE?
HDPE tubes are non-conductive and resist corrosion and abrasion. Aluminum dig tubes come with a non-conductive poly cuff on the digging end, and aluminum extensions are flanged both ends.
Not sure which one fits your truck? Call 402-237-1914 (Mon to Fri, 7AM to 4PM) and talk to someone who has run the equipment.