Unfortunately you didn't include a photo of the very thing you asked about; the "power divider".
GVW=Gross Vehicle Weight, 19,500 lbs means chassis and payload. ( it has 8:25x20 tires doesn't it?)
Transmission code is 5C4 probably a 4 speed but you can look at the shifter and determine that.
Rear axle is self explanetory on gear ratios for a 2 speed diff. C15 means Chevrolet built rear 15K rating.
WB is wheelbase of 157"
CA is Cab to Axle length of 84"
It looks like a 12-13' body to me, certainly it isn't 16' as you claim or you wouldn't even need a hoist. (but might need to chain the front down)
Go back and take pictures of it with the body raised and show the item in question. Then we can help.
