1956 Ford 640 - Fluids confusion

I recently purchased a 1956 640. While trying to replace the 4 bolts in the PTO cover, I wound up loosing a lot of fluid on the shop floor. Researching for the proper replacement fluid from the shop manual and New Holland, I was told to use the 134 hydraulic fluid. I was told the only two fluids needed on this tractor is motor oil and 134 hydraulic fluid since the transmission, hydraulics, and rear end all use the same fluid from the same resevoir. This conflicts with the manual which describes a medium extreme pressure fluid to be added at the fill cap under the right side of the seat.

Can anyone be of assistance by telling which is the proper fluid and where is the correct place to fill the resevoir capped by the PTO cover?

Thank, Brad

I currently conform to the 80/134/80 mentality....for 2 reasons....l. I just changed fluids and that is what I used and 2. I like the thicker oils to keep leakage( as mentioned) down and reduce gear whine. The next time I change fluids I may go all 134....probably depends on what is in the shop.....except for hydraulics..134.....also if you use a common fluid, if you do have leaks you won't be leaking 80 wt into your hydraulics.

Mark

I have decided not to worry about that too much, as long as I change fluids on a fairly consistent basis. With the small amount of use my tractor gets, I'm planning on an "every other year" change frequency on the diff/hyd/trans.

Mark

The three level checks are a pipe plug on the left side of the rear end, dip stick for lift arms (extended), and a pipe plug on the right side of the tranny. Your manual should show all of this. Fred.

I have a different opinion. I tried the 134 in all three compartments, but because it is thinner than regular gear oil I had a lot more seepage from places like the axle trumpets, etc. When I changed fluids again, I went back to 80W-90 gear oil in the transmission and rear end, and 134 in the hydraulic system.

If you have a shop manual, it should show you where the fill points are. The differential fill is on top of the differential. It's a 2" round plug with a square head on it.

Since you just bought this tractor and since you really don't seem sure what's in the diff now, rather than mix something with whatever is in there I think I would drain everything and change all the fluids rather than just topping off the diff.