The internet has been a huge help to millions of people looking for information. It's also been a huge source of widely spread misinformation. There are lots of myths about old Ford tractors so let's see if we can dispel a couple of them on this page.
The first one we'll look at is one we've all heard for years: "The main source of moisture contamination in the "N" tractor transmission oil is from a bad shifter boot." Unfortunately, this widely repeated advice is totally false. The photos below tell the story.
The shifter boot protects the shifter pivot point from dirt and weather so it can remain clean and lubricated.
Some people have gone to great lengths trying to keep the water out of their gear oil - needlessly.
This is the seat or socket in the shifter plate that the shift lever fits into. Notice the curved shape and the solid ring around the bottom of the socket.
The shifter lever has a matching ball shape that fits into the seat.
When assembled the shifter can be moved forward and back and side to side without the ball moving out of the socket. This area was meant to be lightly lubricated and kept clean so the Ford engineers put a rubber boot over it.
The shifter ball is held firmly into the socket by this spring underneath. Look familiar? A ball in a seat held tight by a spring? Maybe like a common valve assembly? When the gears are spinning in the transmission they are slinging oil up against the bottom of the shifter plate like a car wash sprays water. If the ball didn't seal in the socket you would have oil squirting up past the shift lever onto your favorite Big Ben bibs. Just a slight amount of oil will "wick" up onto the ball to keep it lubed.
For our test we've picked up an unmolested shifter assembly and attached a plastic bag around the entire shift lever base using the handyman's secret weapon - duct tape.
The shifter assembly is placed on a sawhorse test stand. This shifter has the boot pulled up out of the way and the external ball/socket area was wire brushed and blown off with compressed air to remove the dirt. The ball/socket area has had no grease, oil, and any type of sealer added to it. It moves freely and is just as it was when removed from the tractor.
A steady stream of water was poured directly onto the shift lever ball/socket area for just over 5 minutes which was about how long it took for me to get tired of standing there holding the hose. A longer test could be done but the results would be the same.
The outside of the shifter assembly and plastic bag was then dabbed dry with a towel and the bag was removed. NOT A SINGLE DROP of water made it past the ball/socket and into the bag. And this was with a steady stream of water and with no boot at all.
So, you ask, where does the water come from? Here is the one and only place rain water can enter the system. The plunger rod enters the lift cover housing through a hole that's sealed only with a felt washer. That seal lasts no time at all. Performing the same water test on this area will show that water can drip into the housing. Even so, it's a very small amount. By far, the vast majority of water that gets into the system comes from simple condensation. Warm oil and cool air makes the inside of the transmission and rear end housings break out in a sweat. So does cool oil and warm moist air. There's a lot of open area inside there so it makes a lot of droplets. Over time it all adds up.
Without a doubt someone will tell me their shifter doesn't fit snugly into the base socket and it can leak water there. If that's the case you've got a severely worn shift lever, a worn or missing retainer on the shifter bottom end, or your spring is broken. Don't worry about boots, fix your shifter before you end up stuck in two gears at once.