Carter

TM 10-1531, the maintenance manual for the WC series 3/4 tons recommends 90W Hypoid gear lube for the transmission, transfer and axles and the winch gears. The pto is lubed with the tranny oil. I would suspect the same recommendations apply to the 1/2 tons but I don't have a manual for them. As far as engine oil is concerned, I don't think 5W30 will cause any problems but I prefered 10W30 for my engine, thinking 5W was a little thin however the winter temps may be a lot different in Everett than they are here in Maryland.