Manual says 90 viscosity. Works well. I.ve used FMD & FPM fore man y years and use the #90 gear oil as Fomoco suggests.. Don,t vary from factory specs..

Tractors up to 1957 used 90W in the gearbox and hydraulics. In 1957 Ford changed the specs in a service letter to use 30W or 20/30W Universal in all tractors, gearbox and rear axle, so both grades are correct.

Do not use 90W in the hydraulics of Fordson Super Majors or any of the Dexta range from 1957 as the porting in the hydraulics is much smaller and the thicker oil will cause problems. (The early Dexta handbook says 140W in the hydraulics and rear axle but this is an error and was changed in later print runs).

I still use the 90W oil in my 1952 Major but the Universal oil in my Dexta.

I guess its a good thing that I have yet to refill the rear end of my Power/Super Major (back half is the Super half). Would oil meeting CIH Hytran be suitable for the transmission/hydraulics? The oil I drained out was like cream colored honey, and the 3point hitch worked poorly. The reprint manual I have is very poorly written.

I would not use Hytran, the Universal 20/30W or straight 30W is what is recommended. Hytran is more like a hydraulic oil.

We used the same oil in engine, gearbox and rear axle back in the day and some of the modern universal oils would be OK in the transmissions but not in the older engines because of the anti-squark brake additives.

This is taken from the original Fordson Repair Manual that we used back then.

thanks. I'll bet the reason the 3pt was so sluggish was the too-heavy oil that I drained out.