It does on the SM420 on my 54 3100.

Checking the gears is a good idea. I had to use a deep thin walled socket to remove the speedometer cable drive. The other gear is held in place by the u-joint yoke. Speedometer gears rarely wear out though. The problem your having is more likely a wore out speedometer head, as was the case on my truck, or it could be the drive cable. Jim Carter Truck has refurbished original speedometer heads. I would avoid the Chinese reproductions. they also have the cables.


Walt Williams