Hypoid Gear oil ?

[rpaszt93]

7.5 open with a 3.73 has a hypoid gear style. but I cant find Hypoid oil so can I just use synthetic oil and run it or what

 

[AgPete139]

You just need an 80W-90 or 80W-120 from your local auto parts store (OReilly, Advance, Autozone, NAPA). Regular differential gear oil is sufficient, and will last you for 100,000 miles. If you are wanting to run full synthetic gear oil for extreme performance with your 2.3L, go ahead, but it is unnecessary. You will need 2.5 bottles of gear oil, of any brand. Castrol, whatever you please. These gear oils are close to the same in quality and price.

You will not see/notice a different in power or fuel economy. As far as longevity and durability, those gears are built to last. You will not be overloading them with your 4 cylinder (not meant to sound condescending). Do you tow heavy loads frequently?

Another thing: if you just installed a new gear in your 7.5, then you will want to replace the gear oil after 100 miles. Do not wail on your gears until after 500 miles, since the new gears must undergo repeated heating & cooling cycles to harden & heat-treat, and wear them correctly.

 

[4x4junkie]

You're looking for 75W-90 or 80W-90 gear oil with a "GL-5" rating. Sometimes it says "Hypoid" on the front of the bottle, sometimes it doesn't. Just look for the GL-5 designation (usually found on the rear of the bottle) and you should be fine.