best gear oil?

Getting ready to change the rear end gear oil in my '47 H. I was planning to use 85W140, as I live in central Connecticut.

Anyone have any preferences as to brand of oil to use, or are all SAE approved oils basically the same?

Art

anything you use will be better than what is in there now. Are you going to work the tractor hard 10hrs per day for long periods of time. We all know its just a hobby thing so use any brand you can find.

That will be fine. At -20 it will be stiff to shift. Jim

That is a good choice. I use it in my M Farmall. Let the tractor warm up in neutral for a few minutes in the winter. Ellis

The H is used for light duty year round. For the next few months it'll be hauling people on hayrides

A 75w-90 or 80W-90 is plenty heavy, even a straight 90 weight if you can find it is what IH recommended. It gets cold in Conneticut, that 140 weight oil will be about like chassis grease at 20 degrees. The rearend of an H or M is SPLASH LUBRICATED, there's pathways cast into the castings to catch and move oil to the bearings that need lubrication. And I can assure you that 140 weight oil will NOT be splashing around below 20-30 degrees. If you have some leaks you don't want to leak anymore replace the leaking seals or gaskets. I have a picture from about 1969 of my Super H with the signs of a bad leaking seal at the input shaft into the transmission, oil was leaking out between the clutch housing or torque tube and the transmission housing and final drive housing. Took a while but finally got the leaks dried up except for the PTO leaks. I have the seals and gaskets, just need to put them in.

I just cringe when I hear guys in cold climates have put 140 weight oil in their H's and M's. I have a 4 ton bottle jack I put 90W-140 oil in and it stops pumping oil below 30 degrees.

You don't want to go too thin of oil either, Dad put Hy-Tran in the '51 M after we rebuilt the transmission and rearend in it one summer, all new bearings, seals, & gaskets. No leaks but it took a while to shift into any gear after you pushed the clutch in, much much less oil drag on the gears to slow them down. Took about 30 seconds to shift into gear without clashing gears when oil was warm. Went back to 90 weight and shift time dropped to 2-3 seconds.

85W140 will be just fine
the 85 part of that rating is the cold rating so it is very little difference than stright 90 in the winter