Rear ends and manual transmissions usually call for lubricant to be added to the bottom of the fill hole. i.e. when it starts runnin' out, it's full!
Oops, a quick check of the shop manual says its should be 1/2" down from the filler when cold. At the bottom of the filler hole when at operating temperature.
1-1/2 and 2 ton trucks went to open driveshaft about 1941.
1-1/2 & 2 ton single speed rear end holds 12 pints of lube. 2-speed holds 14 1/2 pints. 4-speed transmission holds 6 pints. Both use S.A.E 90 "Multi-Purpose" gear lubricant.
