A steady drip of oil from your John Deere 6-cylinder back end is not a quirk.
It is your load control shaft seals waving a white flag.
Ignore them and the back end will happily pump its oil onto the yard.
In this guide, you fix those seals in about 20 minutes and keep the tractor working, not weeping.
What the load control shaft does on 6-cylinder tractors
The load control shaft runs through the rear housing and links draft control to the linkage.
Seals around the shaft keep transmission and hydraulic oil inside the back end.
Worn seals let oil drip or pour out under the tractor.
Left alone, the rear end can empty itself and starve pumps and gears.
Which tractors this guide covers
This guide covers 6-cylinder John Deere 20, 30, 40, and 50 Series tractors.
The layout and steps match the shaft and housing on these models.
Shaft diameter still changes seal size, so you must match seals to your shaft.
Tools and parts you need
- You need new load control shaft seals for your tractor and shaft size.
- You need a good pair of pliers.
- You need a 5/16 punch.
- You need a hammer.
- You need a small pick.
- You need emery cloth or similar abrasive strip.
- You need a topped up oil can.
- You need clean rags.
- You also need patience and a bit of space to work.
Why this job matters on 6-cylinder tractors
Fresh seals stop the rear end leaving oil on the floor.
Good oil level protects pumps, valves, gears, and brakes.
Dry castings make it easier to spot future leaks.
A 20 minute seal change beats a full rear end rebuild.
Safety and preparation
Park the tractor on firm level ground.
Apply the handbrake and chock the wheels.
Lower the linkage and remove any mounted kit.
Switch off the engine and remove the key.
Clean the rear housing before you start work.
Step one: remove the linkage from the load control shaft
Start by getting the linkage off the load control shaft area.
Remove the spring clip that holds the linkage pin.
Use pliers and keep control of the clip so it does not fly across the yard.
Spring clips love to hide in gravel and straw.
Knock out the retaining pin with the 5/16 punch and hammer.
If the pin is seized, use controlled force and persistence.
Brute force and ignorance still need some aim.
Step two: slide the bush off the shaft
Once the pin is out, slide the bush off the load control shaft.
Expect the bush to feel tight after years on the tractor.
Work it off with a steady wiggle, not big hits.
Avoid marking or scoring the shaft as you move the bush.
Step three: drain the transmission oil
Place a suitable container under the drain plug.
Undo the plug and let the oil drain in a controlled way.
Wear gloves because this bit is messy.
Use rags to catch drips and keep the area as clean as you can.
Step four: disconnect all linkage from the shaft
Disconnect any remaining linkage arms from the load control shaft.
Take photos so you can refit each piece in the same layout.
Leave the shaft ends clear so you can see wear and seals.
Step five: check shaft and bushes for wear
Clean the exposed shaft with rags.
Use emery cloth to remove light rust and shine up the shaft.
Inspect the shaft and bushes for grooves or flat spots.
If it looks like your grandad’s knees, you may need more than seals.
Bad grooves can justify a new shaft or extra work later.
Step six: clean the end of the load control shaft
Give the shaft end a full spa treatment with cloth and emery.
Remove dirt, glaze, and rust where the seals will run.
Clean metal helps new seals seat and last longer.
Step seven: remove the first flange from the tractor
On the 6-cylinder setup, remove the first flange from one side.
Undo the fixings and pull the flange away from the housing.
This step gives more space and cuts the swearing later.
Step eight: remove the old seal and fit the new one
With the flange off, expose the old seal in the housing groove.
Use the small pick to lift the old seal out carefully.
Avoid gouging the housing as you lever the seal.
Clean the groove with a rag and emery if needed.
Fit the new seal into the groove in the housing.
Press the seal in nice and steady all round.
This step needs finesse more than force.
Refit the flange back onto the tractor and tighten the fixings.
Step nine: repeat on the other side
Move to the opposite side of the tractor.
Remove the second flange in the same way as the first.
Remove the old seal from that side and clean the groove.
Fit the second new seal into the housing.
Refit the second flange and tighten the fixings.
Step ten: centre the shaft and refit linkage
Check that the load control shaft sits centred in the housing.
Confirm equal exposure of the shaft on both sides.
Refit the bushes onto the shaft ends.
Refit the linkage arms to the shaft.
Install the retaining pins and spring clips.
Check the linkage moves smoothly through its travel.
Step eleven: change the hydraulic filter and seal
Spin off the hydraulic or transmission filter housing.
Remove the old filter element.
Clean the housing and sealing faces with rags.
Fit a new filter element matched to your tractor.
Fit a fresh seal on the filter housing before refitting.
Tighten the housing by hand until it seats correctly.
Step twelve: refill with oil and check for leaks
Refit the drain plug with a sound washer.
Refill the transmission and rear axle with the correct oil grade.
Use the oil can if you need to prime specific circuits.
Start the tractor and run the hydraulics for a few minutes.
Stop the tractor and inspect both sides of the load control shaft.
Look for fresh oil around the new seals and flanges.
Dry castings mean you nailed the job.
Wet streaks mean you need to pause and check seal seating.
Common mistakes with 6-cylinder load control shaft seals
People skip cleaning and pull grit into the housing.
People drag the pick across the housing and score the groove.
People rush seal seating and leave one side twisted.
People ignore heavy shaft wear and blame the new seals.
People forget to change the filter while they have the oil out.
When to call Nick Young Tractor Parts
If the shaft looks beyond hope, ask about new shafts and bushes.
If you are unsure on seal size, share shaft details and tractor series.
Nick Young Tractor Parts can cross reference 20, 30, 40, and 50 Series setups.
The team can also supply filters, seals, and oils as a matched kit.
Quick recap: fitting load control shaft seals on 6-cylinder tractors
Remove linkage and bushes from the load control shaft.
Drain transmission oil and clean around the shaft.
Remove the first flange, replace the seal, and refit the flange.
Repeat the flange and seal job on the other side.
Centre the shaft, refit linkage, and change the filter and housing seal.
Refill with oil, run the hydraulics, and check for leaks underneath.
With this 6-cylinder load control shaft seal guide from your video, your blog can turn quick fixes into reliable tractors and better informed customers.
