Most of the gasoline powered fire trucks were dual ignition and have a place on the distributor for a tachometer. The speedometer was attached to the PUMP transmission. When the truck is pumping, the transmission is in high gear unless it is an overdrive trans, then it is pumped with the trans in 1 to 1 gear. There is a large PUMP transmission that is linked in behind the conventional trans. To engage the pump, the pump transmission is engaged and it throws the drive shaft that goes to the rear axle into neutral and it turns a short drive shaft that turns the pump. While the truck is pumping, the speedometer is at idle, but the tachometer is still going. The engines are running pretty hard when the truck is pumping. Never judge a pumper truck by its road miles!
Last edited by c Jason Barnett; 09/02/2012 3:41 PM.
