Two Speed Rear-end Help

[beatngu]

on the '76 international dump truck my family just got, there is a box off the side of the pumpkin. The damn truck will only do 35 in fifth gear floored. On the dash there is a factory sticker which explains how to use split shift, or a two speed rear-end. In the truck there is not a lever, or visible button to change the rear's ratio, so my question is what is the real purpose of the box?

[greg]

"There should be a switch on the shifter that you pull up or down , up is in hi down is in low. The 2 speed motor on your pumpkin doesn't look like it is hooked up . I don't see any wire going to it. The purpose of a 2 speed rearend is to allow you to take half a gear. Instead of splitting the gear in the transmission you are doing it in the rearend.

greg

[beatngu]

There is a few yellow wires that are hanging under the frame, my step dad said they were going to it I believe. If anyone wants to see them, or any other aspect of this truck to help me figure this crap out, feel free to ask! oh, and the shifter does not have a switch on it.

[mackmixer]

Try tracing the yellow wires up to your cab. You could have a dash mounted toggle switch or a floor mounted dimmer switch to shift the motor.

[Packer]

Just been puttering with a two speed (Mack) The vertical round thing is a D.C. motor that is hooked to a 'screw' that runs the low and high part of the diff.

Should be two posts on the 'can' that the wires attach to.

Just bought a rebuild kit for mine @ $48.00 for all the goodies.

Packer

[beatngu]

Thanks a ton for the dimmer switch hint! I think I have found it thanks to all the help here.

[beatngu]

Well, I am going to clean all the gunk off the the rear-end, and attempt to reconnect the wires. I am just curious as of to why they are off in the first place.