801 PTO outlet seal replacement help

[WGregB]

Looks like I posted this in the general forum earlier, so I am trying again in the Ford forum. I have a 1959 SOS with a single speed PTO (871) that was in a fire about 2008, and has been sitting since then. I have just completed getting it back to running condition. Is it possible to replace the PTO output seal without removing the PTO shaft? I have reviewed the PTO overhaul section of the Ford manual. I have also just drained and refilled the hydraulic section. After draining the differential and upon filling it, I discovered why it had less than two quarts of fluid in it; the fluid flows out of the PTO seal. I am not looking forward to draining and refilling the hydraulic section if I don't have to, so I am asking the people who know. If I have to remove the PTO shaft I am guessing I will have to drain the hydraulic section as well as the differential since the shaft and its inner seal fill the hole between the two systems, right? Thanks.

 

[Sean in PA]

You don't technically have to drain either compartment to replace the seal, but yes, the PTO shaft and the squarish plate that it is protruding from have to come out. If it's already down to the level of the bottom of the PTO shaft because of the leak, if you park it on a hill nose down, you might lose a little of the fluid once the trans fluid makes its way back there, but it shouldn't be too much.

 

[WGregB]

Looking at the cutaway on page 274 of the Ford shop manual it is hard to tell, but it looks like there is a sleeve that the
PTO shaft runs through as it transverses the hydraulic section. Is that correct? So the seal between the hydraulic section and
the differencial is around the sleeve, and not the shaft? If so, that would prevent the hydraulic fluid from running into the
differencial with the PTO shaft removed. That would clear up my main concern about removing the PTO shaft. Do you happen to
know the part number for the output seal so I can have it on hand before I pull the shaft? Thanks for your help.

 

[Sean in PA]

In looking at the parts drawing, it looks like the PTO shaft that is in the transmission comes through the bulkhead into the rear axle where the splined coupler is that engages that shaft to the actual PTO shaft that sticks out the rear of the tractor, so I think you might be correct in that seal for the forward shaft will keep fluid from getting from the hydraulic sump into the rear axle.

The part number for the PTO output shaft seal is D9NN703BB. You will also want a replacement gasket that goes behind the square plate, which is part number 81801907.