Any Old School Mechanics out there?

[Theekillerbee]

I have a friend with an old (64) F600 dump truck with a 2 speed differential that is having problems. You can free spin the yoke, and see the planetary gear in the back spinning, but it doesn't engage the axles. We haven't split the diff yet, but any thoughts would be appreciated.
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[GEEZER]

Check first to be certain the 2 spd. shifter on the diff. is all the way one way or the other. If it's electric, you might even have to pull the motor off & turn the shifter drive by hand. If it's an old vacuum shifter, disconnect the diaphragm & move the shifter rod in & out. If the shift collar in the diff. somehow gets stopped between ranges-- just like neutral.
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