Posted 8/20/2013 09:47 (#3277758 - in reply to #3277719) Subject: Re: What oil should i use for tranny and rear diff on 1977 GMC 6500?
S.E. Sask.
Yes, I've read that EP gear oils are not recommended for many truck transmissions. I've been using straight grade #30 engine oil in the transmission of my IH Loadstar for years and it works fine. Rear end has 85-90 gear oil.