The Fordson Tractor Pages Forum

Hi everyone, I filled my fm from front t back with sae30 oil. But yesterday i was talking with an engeneer from shell, and he told me the sae30 should not be used for hypoide gears. He says the big hypoid gear in the backend will not be sufficiently lubricated to avoid wear. I know the factory says sae 30 is ok, but oil from the 60's isnt the same as today.
thanks

As you do not have a Hypoid gear in the rear axle 30W is fine. Your Shell man may know about oils but I would suspect his tractor knowledge.

If i am not mistaking the gear on a fm differential is a hypoid gear. If you look on the 3 photo on this page you see the gear on the top: http://www.fordsontractorpages.nl/ubb/F ... 00138.html
And here is the wiki page:
http://commons.wikimedia.org/wiki/File:Hypoid_gear.jpg

They are not Hypoid gears. Hypoid gears are usually found in car and truck differentials and have a different type of pinion to crown wheel engagement. They have a more "rubbing contact" if you get what I mean and are used at higher speeds. If you look at the shape of the teeth in the drawing of the pinion you can see a difference, the tractor ones are more a straight cut. The gears in tractors are more like a bevel gear.

I do not know any make of tractor that has a Hypoid rear axle but I have only been working with them for 45 years and am still learning.

Hypoid rear axle oil can also affect the bronze thrust washers used in tractor rear axles.