In Reply to: GL-1 posted by Dean on March 25, 2018 at 07:58:59:
I know this isn't what you asked, but here is a post (see LINK) from our archives regarding the GL-1 and the GL-5 grade oils. There is also a ton of other good info in the archives on hydraulic oils. If your concerns are with affects on yellow metal, there is very little yellow metal in N's so not using a GL-1 will not harm anything, and what type of oil depends too on what climate you are in as well. Everyone has their own preference/theories and you can do whatever you wish as it is your tractor. TSC sells, or use to sell I don't know, haven't been in one lately, a GL-1 oil, essentially an SAE90 oil, labeled 'specifically for old Ford Tractors' under their TRAVELLER brand. CNH continues to distance themselves from old Ford Tractors and have discontinued supplying the Ford MC134-D spec'd AMBRA oil.