Farmall H output shaft oil seal

Greetings. I have an oil leak at the output shaft oil seal on my 1945 H. I've disconnected the lift-all drive to check and there's a serious amount of oil around the coupling each time I run the tractor. I've never needed to do this job before so any advice would be good. My main concern is whether its a standard Right Hand Thread because I certainly don't want to cause any stupid damage. So I would really appreciate any help, suggestions or advice that you can give. Thanks in advance. Mike Farmer

You"re talking the shaft that comes out of the transmission, connects to the 2-bolt coupler, that in turn connects to the 4-taper-bolt wavey-looking connector? Then yes on my 1950 H, that 2-bolt coupler was held on by a right hand thread bolt, which unbolts fairly easy. I think it"s 3/4" or 5/8".
Now it may get interesting. The coupler connects to the shaft by a Woodruff key, and mine had deformed enough it took me 48 hours of prying / pulling / coaxing / pushing / hot-lubricating-words to get it off. Some guys say theirs just slides off, I hope yours does. To me, it"s an IH mistake; transmit all that power through a Woodruff key? Mistake, should have been a splined shaft.
Two cautions; the taper-bolts are pricey, maybe irreplacable, be careful with them.
Second, LOOK NOW at how the wavey-4-bolt-connector-plate. It HAS to go back on like it came off, with space in it. It WILL bolt back up in a "compressed" fashion, but the drive shaft will not sit back in the pilot bearing, it will flip and flop, it will be out of the pilot bearing, it will cause damage. LOOK at how it sits, put it back the exact same way.
Some guys say this 2-bolt coupler slips right off, and I hope your does. Mine didn"t. ;

If its the output or counter shaft driving the liftall, the slotted drive coupling nut is standard or right hand threads. Remove it and the three bolts retaining the seal housing. Remove it and replace the seal. Housing also originally uses a gasket to transmission housing. Transmission oil will come out when removing unless drained down or front of the tractor pretty high up.

There is a right way and a get by way to work on that shaft. The right way is to pull the housing with the shaft and bearings. Held in with them six bolts. Then you can repair it right, checking the bearings for wear and more importantly, be able to access the transmission pilot bearing which was the highest failure rate bearing in the H tractor. You need to pull the belt pulley drive off to do this or you will damage bearing putting it back together. I have seen more than a few put back together where the half moon key moves back up the key slot and then it damages the yoke when bolted down tight.

Hi again. Thank you all for your input. Now I can approach this problem from a more informed standpoint. Again Thanks. Mike Farmer