I am trying to get some sae 30 hd oil for me gearbox without success I can get sae 30 sa i beleive the differance is hd is heavy duty and sa light duty.Is the sa ok and were can i ger hd oil if it is not ok.
FWIW I changed the oil in a Twin Disk MG506 (VP Engine)some time ago and the manufacturer was very insisistant that I used the correct oil spec which I am sure was SAE30CD. I put in ordinary SAE30 (from Halfords - Garden machinary oil) and was advised to remove it and replace with SAE30CD which I did. Thought I would mention this as gearboxes ain't cheap!