Hi/Lo Axle Problem

[koehlerle]

I have a 1974 Ford 21/2 ton Farm type dump truck. I suspect the Hi Lo axle engaging mechanism is not engaging or functioning properly. The symptom is that the the truck will move in reverse but in any forward gear the drive shaft turns but the differential isn't engaged and the gear shift knob does not seem to function. I need technical information on and specs for how the Hi Low mechanism works (schematic).

Thank you,

koehlerle

 

[blacksnapon]

I have a 1974 Ford 21/2 ton Farm type dump truck. I suspect the Hi Lo axle engaging mechanism is not engaging or functioning properly. The symptom is that the the truck will move in reverse but in any forward gear the drive shaft turns but the differential isn't engaged and the gear shift knob does not seem to function. I need technical information on and specs for how the Hi Low mechanism works (schematic).

Thank you,

koehlerle

Our problem is that after 10 years old, schematics are scarce. Just the fact that the driveshaft turns and nothing is happening puts the problem back at the differential. Is it air or electrically operated?

 

[koehlerle]

Hi Lo Axle Problem

Thanks for your response.
There is a push pull (old vent pull type) on the 4 speed floor gear gear shift.
It is attached through a cable and a white wire to a junction type assembly that I can't see into but there are two rubber hoses going back from it to the differential so I anticipate that it is air operated. I suspect that the actuating mechanism is not fully controlling the air or vacuum valve and the pinion or mechanism in the differential is in a neutral kind of position and is unable to be controlled by the push pull activation knob. Just a description of how it works and if my diagnosis sounds plausible would help a lot. If you have a web link that might describe the operation it probably would have a general schematic description of the system.

Thanks, koehlerle