I was referring to my owner's manual which suggests 'Hypoid gear oil SAE #80'. Unfortunately, I wasn't able to find any SAE 80 gear oil at my local auto parts store, so, I bought a synthetic blend SAE 75W90. Bottle says meets requirements for all hypoid and other gear types - - meets APL GL-4, GL-5, MT-1 and Military MIL-L-2105E specs. Says it's recommended for differentials in cars, trucks and off-road equipment. Should I be OK using it? Thanks in advance for your suggestions!

 

You'll be fine,the 80 weight is the factory lube,for temperature ranges that will allow it to flow and lube your ring and pinion.The synthetic you bought is even better,wider temp range protection,and will last longer than normal gear lube. Synthetic also resists mixing with water better,so a couple of deep water crossings won't destroy it near as fast as regular lube.

 

95wolv is right.

You will be okay with what you are running.