From my shop manual for 42 to 46 trucks
Universal Joint Lubrication
Passenger car and 1/2 ton truck
The universal joint is directly conected to and recieves its lubrication from the transmission. The universal joint housing should be filled through the speedometer driven gear hole, for initial lubrication after a repair opeation. This initial lubrication is necessary to take care of the universal joint until normal lubrication takes place from the transmission.
NOTE --- The pipe plug in the top of the front universal joint housing onthe 1/2 ton optional 4-speed transmission is for manufacturing purposes and is used to fill the universal joint at the time of assembly.
3/4 and 3/4 ton special (124 I/4" wheelbase) Models
(3-speed transmission)
The front universal joint, immediatly to the rear of the transmission is of the trunnion bearing type and recieves its lubrication from the transmission. Additional lubrication at this point is unnecessary. The battery ground strap bolt hole in the housing is used to fill the front univeral joint at the time of assembly and after repair operation.
NOTE -- The pipe plug is the top of the front universal joit housing on the 4 - speed transmission (optional equipment) is for manufacturing purposes and is used to fill the front univeral joint at the time of assembly.
The intermediate and rear universal joints are the needle bearing type equipped with lubrication fittings, and should be lubricated with the same type of lubricant used in the transmission.
CAUTION -- Under no consideration should any of the soap type of greases - such as chassis lubricant, fibrous universal joint lubricants, etc, be used.
The propeller shaft slip joint, located at the rear of the intermediate universal joint is also equipped with a lubrication fitting and should be lubricated with chassis lubricant.
