Comment
If it is a WD model it should have a filler spout fitted with a blanking plug cast onto the rear of the main gearbox case...
If it is a 'civvy' post war model it is filled through the front of the outer cover after removing the circular cover that gives access to the clutch pushrod adjuster screw...
WD boxes struggle to accept the 1 pint of sae 40 specified...About 3/4 pint will fill them...
Nightmare scenario is that you have a WD box with a post war main casing...In that case there is nowhere to put the oil in! Unless that is, you remove the inspection cover and baffle plate on the upper rear face of the box..and that is a very fiddly job!...Ian
email (option): ian@wright52.plus.com