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Ford Tractor Hydraulic System

All N-Series Tractors - Ford-Ferguson 9N, 2N, and Ford 8N

As with other things, I like to tackle any sort of lift problem by first checking the possible causes that are No-Cost or Low-Cost items. So, how's the weather? There's a good reason to talk about the weather, it affects everything.

1 - Has it rained or been humid recently?
2 - Did it freeze last night?
3 - Is it below freezing now?
4 - Do you leave your tractor parked outside?
6 - Has it been more than a year since the fluid was changed?


Almost left this one out. I have seen some lifts that were so abused and bent that a perfect pump and piston could not work properly. Straightening and repairing the lift arms and other hardware is mostly just time and energy. If someone has substituted bolts where there should be pins, replace them with the correct hardware. If you don't have tools to straighten what is bent, new parts are available. A shop press is ideal, but creative use of a floor jack or bottle jack and heavy chain can straighten lots of parts. Any improvement will help. BE CAREFUL! Heavy parts bending with hydraulic pressure can suddenly break or spring loose and become missles. Don't put your body under or in line with any force you are employing. I got in the habit of wearing safety glasses 100% of the time in my shop. Wear them enough and you forget you have them on.


Water in the hydraulic fluid is very bad. First, it causes rust and corrosion. Even small amounts of water in the pump can cause valves to stick, springs to break, or linkage to bend. Water is heavier than oil, so it collects at the bottom of your sump (where the pump is located). It is a good idea to drain off any water that may have accumulated. It's not a bad idea to crack the engine oil sump plug loose while you are under there.

How does water get inside the sump? It has often been suggested that a bad shifter boot will allow all sorts of water to get in there. That is not true for any of the ford tractors I have. The shifter is a ball and socket, that seals fairly well,even with no oil on it. The transmission slings oil around inside the housing, so the shifter ball and socket is usually well lubricated. No water is getting past a ball and socket with lube on it. The shifter also sits well above the surface of the transmission cover. So, if water isn't getting past the shifter, where does it come from? Simple condensation. The fluid level in the transmission/hydraulic sump is way less than half full. The rest of that space is air and metal. When the metal is cool and air is warm, condensation forms on all that metal. A little condensation, every single day, quickly adds up to a pint or more of fluid in the sump. Think about how much water one ice tea glass can leave on a table. Now, multiply that by however many ice tea glasses it would take to equal the same surface area of metal that is inside the tractor sump.

Water is bad, ice is worse.

If temperatures have been below freezing, warm things up by bringing the tractor into a garage or use a portable heater. Once things are warm enough not to be frozen, get a pan or pail and crack open the three drains at the bottom of the hydraulic sump. Do them one at a time and only crack them open. What I mean is only unscrew them enough to let the water run past the threads. When the water stops, turn the plug closed again. Water will go right past the loosened threads, the thicker fluid won't come out unless you go too far. Do that and you will have several gallons of oil in the face or running down your arm as you frantically try to thread the plug back in.


Draining water as it collects in the sumps can help to extend the fluid change interval, but the fluid does not last forever. Dirt and other contaminants collect in the fluid and there is no filtration to remove them. Additives that help prevent deposits and corrosion wear out. The Operator's manual says to change the fluid every 600 hours. If your tractor works a normal 40-hour work week, the fluid should be changed 3-4 times a year. Many of our tractors are only weekend warriors or less, so maybe the fluid only needs to be changed once or twice a year. Make an honest estimate of the hours your tractor is used each week. Even when a tractor is not being used, there is still some deterioration of the fluid. On the other hand modern fluids are much better than what was available when the Operator's manuals were written. Weigh those facts, and it probably works out that even a lightly-used tractor should have the fluid changed at least once a year. Looking at the condition of the fluid when checking the level can help indicate when the fluid should be changed. Extending or neglecting to do fluid changes only guarantees thaat there will be problems caused by moisture, dirt, deposits, and corrosion.


The N tractors have a common sump for the rear end, hydraulic pump and transmission. Therefore, the fluid used in these Ford tractors is a combination gear lubricant/hydraulic fluid. The original fluid recommended by Ford for the 9N tractor was “Straight Mineral Oil, SAE 90"”. For winter use in really cold climates SAE 80 could be used. This fluid would correspond to the now inactive API Gear Oil designation GL-1.

Oil technology has improved over the years. Around 1950 Ford changed the fluid recommendation for all N-tractors to: “Mild EP GEAR OIL conforming to Ford specs M4864A (SAE 80) (below freezing) or M4864B (SAE 90) (above freezing)”. This fluid would correspond to the now inactive API Gear Oil designation GL-3.

Oil technology continued to improve. What does the "dealer" recommend today. In case you didn't know, in 1994 Ford sold the tractor division to New Holland group. In 1999 Case/IH and New Holland merged, to form CNH Industrial. In 2012 N.V. Fiat and CNH became CNH Industrial N.V. Parts for N-tractors can still be ordered from the New Holland parts department and web parts store. The fluid they recommend for all "N" series tractors is a combined hydraulic/transmission "Multi-G 134" fluid (NH-410B). The NH-410B is the current CNH OEM specification that is equivalent to Ford ESN-M2C-134D. This combined hydraulic/transmission fluid is a modern product with additives that works well as both a hydraulic fluid and gear lubricant. Any product that "meets" the NH-410B specification is much better than any straight mineral oil or M4864 fluid. The transmission and differential gears will last longer, and hydraulics will work better.

If we wander into the local Tractor Supply Company ®, or even WalMart®, and start reading labels, we find several "Universal Tractor Fluid" products:

Traveller ® Ford Tractor All Mineral SAE 90 Ford Tractor Transmission Fluid. This is as close as you are going to find to the originally recommended fluid for the 9N and 2N tractors. This is probably going to be the least expensive fluid available. If you are on a tight budget, or have 6 tractors that need changing, this may be the one you buy. This is certainly not the best fluid available. Remember, the fluid recommendation has been upgraded twice since any of the manuals said "straight mineral oil". If you want something better, look for a universal tractor fluid that says "meets" NH-410B or M2C-134D on the label.

Shell Rotella HD Tractor Transmission and Hydraulic Fluid meets API service GL-4. This is a UTF, but it apparently does not meet M2C134D.

Traveller ® RENEW for Older Tractors, Universal Tractor Trans/Hydraulic Fluid. This is a UTF, but it apparently does not meet M2C134D.

Traveller ® Premium Universal Tractor Trans/Hydraulic Fluid. Same as above. Read the label carefully. This one may actually say something like "recommended for use in place of" Ford M2C-134D fluid. The question that should be asked is "who" makes this recommendation?

Super Tech Heavy Duty Tractor Hydraulic and Transmission Fluid sold by Walmart ® says right on the label "meets Ford New Holland ESN-M2C134-D specification". This is the right stuff.

The NH-410B (M2C-134D) type fluid is thinner than 80 or 90 weight gear oil. For me, this means it works better year-round. No warm-up needed on cold winter mornings to get the lift to work. Less problems with cavitation for my live hydraulics external pump. Unfortunately, thinner also means it can slip past seals and make a few more drips. For a trailer queen, we would rebuild all of the seals to stop the drips. My tractors are working tractors. I don't mind if they mark their territory with an occasional drip. If a leak gets worse than a few drips, time to fix it.


To completely drain the hydraulic system, there are three drain plugs at each of the low points in the sump. Two large plugs under the transmission, and hydraulic pump, and one smaller pipe plug under the differential housing. There is only one filler cap located on top near the gear shift lever.

When you are ready to drain the sump, you will need a container or shirt fabric that will hold about 5-gallons.

When changing the fluid, try to flush as much of the sludge as possible out with the old fluid. Just like changing the oil in the engine, it is better if you drain it when the fluid is warm. It runs out quicker and more "stuff" is suspended in it. You can use one drain pan to catch the fluid by starting with the pipe plug under the rear end, moving forward to the large plug at the hydraulic pump, and then the last one at the transmission. I recommend starting with the small pipe plug at the back. The smaller hole is easier to control.

Some people recommend flushing the system with kerosene or diesel fuel. They drain the sump, replace the plugs, pour in a couple of gallons of kerosene, start the engine, engage the PTO and run the lift up and down a couple of times. Then they remove all three plugs, and let it drain overnight. This procedure of-course requires three drain pans and you probably won't want to do this in an attached garage.

The fluid we find in most of these tractors is often sadly neglected. It may not have been changed in many years. All of my tractors had a layer of nasty sludge in the sump that was not going to come out with any ordinary flushing. I dropped the belly pump and removed the hydraulic top cover. This allows the pump to be tthoroughly cleaned by hand and provides some big holes to work thru to clean out the sump.


Once the sump has been completly drained, make sure all three drain plugs are tight, then remove the bottom bolt from the side inspection cover that has the hydraulic dip-stick (the tractor shoudl be on level ground). Start filling the sump. STOP when the fluid begins to leak out of the bolt hole. That is all you need, any more will just leak past the axle seals and get on your brakes. It usually takes 4-1/2 to 4-3/4 gallons not 5 as stated in the owners manual. Pull the dipstick and see where the level is. If necessary, make a new mark that corresponds to the correct level. The reason we don't trust the marks on the dipstick is that the originals were easily broken, and may have been replaced with one from almost any other vehicle.


A lift that raises slow and won't stay up when the engine stops may have blown gaskets, cracked cylinder, or other internal leaks. Attach a heavy implement (anything weighing at least 150 pounds should be enough). Remove the right inspection plate that has the hydraulic dip-stick. Start the tractor, press the clutch, make sure the PTO is engaged. The PTO shaft should spin when you release the clutch. Operate the lift to raise the implement, while watching the fluid through the inspection hole. Look for leaks coming from above. Small leaks have a tendency to get bigger, but you should be able to judge if your leaks are bad enough to have to remove the top cover and fix them. Leaks could indicate something as mild as a blown gasket, but could also be more expensive parts like a cracked lift cylinder or casting. A mirror can be used to try and pinpoint where the leak is. A new top cover gasket set is pretty cheap.

Removing and replacing the top cover is a relatively simple proceedure that is covered pretty well in the I&T FO-4 manual. The only thing I can add is that it helps to have two people, one to do the heavy lifting, another to stick their hands in the goo and guide the linkage into place as the cover is lowered. It is hard, but not impossible, to do both with only one pair of hands. Any overhead lift is a great help. DO NOT start to bolt the top cover down until you have made sure the linkage is correctly placed and not binding. Never force anything! If it won't go easy, stop and figure out why. The two-sided linkage on the 9N/2N is a much bigger pain in the rump to get hooked up. Don't attempt to do it from just the right side cover. You need to be able to grab both pieces and stretch them into place. You will want to do this when the wife isn't around. There is no way to explain why you were hugging your tractor with one arm in each inspection hole. GRIN

If you do need to remove the top cover, that is a good time to check, repair, and readjust the linkage. I can add very little to that procedure. It is possible to repair and adjust your lift using just the instructions in the I&T FO-4 manual. The 9N-2N lift is much simpler with only one external adjustment.


While you are looking for leaks, you should see some indication that fluid is being sucked into the pump from the sump. No leaks, and no indication of suction, could be stuck valves or something major broken in the pump. FIRST push the clutch in and make SURE the PTO is engaged. Drain off some fluid to expose the top of the pump. This should allow you to see if the excentric cams and pistons are moving properly. There are two piston assemblies that should move at the same time, and in opposite directions. A "chuckling" sound under load usually means the excentric cams are worn but the pump can make a lot of noise and still work ok. Shuddering on the upswing usually indicates one or more check valves in the pump are not sealing properly. Rebuild kits can be purchased in various stages depending on what needs to be rebuilt. Once again, I have little to add to the diagnostic and repair proceedures in the I&T FO-4 manual.

Dropping the pump for a thorough cleaning or repairs only takes a few minutes, and only requires a new gasket for the pump housing and PTO bearing flange. Drain the sump. Remove the PTO shaft. There are four bolts around the PTO bearing flange. Remove those and the shaft pulls straight out the back. Check the bearing. If that is loose or the seal was leaking, plan on replacing the bearing and seal while you have it out. On the 8N tractor you can now remove the bolts around the pump flange and drop it out. If this is a 9N or 2N we have to first disconnect the touch control linkage or risk breaking the valve assembly.


The most common problems with the 8N linkage are wear and bent linkage. Look at the 8N link that goes down to the valve. It should be straight. If that link is bent, the top cover has to come off and there are usually other parts that need attention. Most are covered well enough in the manual. The 9N-2N linkage is different and not usually bent. However, before removing the top cover or dropping the pump out of the 9N-2N tractors, the linkage must be disconnected. Accomplishing that when working alone is easier said than done. Reconnecting the links, even with a helper is more difficult. The linkage is spring-loaded. How does one person pull out on the touch control linkage from both side covers, at the same time? I've done this with the seat removed, laying on the tractor, with an arm in each hole. There has got to be a better way. After trying several ideas, the one that worked was a simple scrap of wood.

The scrap was cut to 0.375" x 0.75" x 3.75" and wedged between the two linkage arms with one hand, working through the right inspection hole, with the touch control lever in the full DOWN position. With the wooden wedge in place, we can now reach under the tractor and tickle the valve link loose while still looking thru the side inspection hole. Piece of cake, and there is no need to remove the other inspection cover.

Reinstalling the cleaned, replacement, or rebuilt pump can be tricky. The pump has to be wiggled up into place and then the front edge of the pump overlaps the front lip. It helps to have something like a block of wood under an elbow or a floor jack to help hold the pump when it does not go in perfectly on the first try.

Once the pump is back in place, reach thru the drain hole and put the valve links at the pockets on each leg of the linkage, then carefully pull the wooden wedge out, hopefully capturing both sides of the valve assembly in the pockets.

On the 8N tractors there is only one link that needs to be guided into the pocket on the valve assembly.


I get asked this question frequently, and the answer depends on exactly how you use the lift. The 3 point lift will pick up a lot more weight close to the tractor, than it will out on the end of a boom pole. It also depends on how much weight you have on the front end. With about 800 pounds on the lift arms, the front tires start to come off the ground. I've seen a 1200 pound round bale on a 3-point bale spike on the back of an 8N, but he also had a loader bucket on the front to help balance the weight. It can be done, but I think that qualifies as abuse.


This one is a separate page Live Hydraulics. Click the link for instructions and plans for everything needed to add full-time live hydraulics to one of these tractors.

RETURN - to main TUNE-UP page or go to the next subject BRAKES


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