Your John Deere rotary mower—whether it’s an MX5, MX6, MX7, MX8, or MX10, it is well known for it's durability, but like all hard-working farm equipment, it demands consistent care. Proper maintenance not only extends the life of your mower but also improves cutting performance, reduces downtime, and prevents costly breakdowns.
This guide provides a step-by-step look at routine maintenance practices every John Deere mower owner should follow. From lubrication to seasonal prep, these tips will help you keep your mower in peak condition and ensure you’re getting the most out of your investment.
Routine Lubrication and Grease Points
One of the simplest yet most important steps in John Deere mower maintenance is proper lubrication.
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Blade Spindles and Bearings: Apply grease to spindle zerks regularly. This keeps blades turning smoothly and prevents bearing wear.
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PTO Shaft U-Joints: Grease the cross bearings and telescoping shaft at intervals recommended in your operator’s manual.
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Wheel Bearings (if equipped): For pull-type models, grease wheel bearings before every season.
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Lift Linkages and Pivots: Don’t overlook pivot points; they are prone to seizing if neglected.
👉 Consistent greasing reduces friction, protects against rust, and ensures smoother operation across the entire mower.
Checking and Tightening Bolts and Fasteners
Rotary mowers operate under high vibration loads, which can loosen hardware over time. A quick fastener check should be part of your routine:
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Blade Carrier (Stump Jumper): Verify the large retaining nut is tight. Loose carriers can cause severe vibration and gearbox damage.
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Gearbox Mounting Bolts: Inspect for looseness or signs of deck cracking around bolt holes.
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Blade Bolts: Ensure each blade bolt is tight and secure with proper locking hardware.
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Safety Shields and Guards: Tighten fasteners around PTO shields, driveline covers, and chain guards to prevent accidents.
Keeping bolts torqued to spec prevents misalignment, minimizes vibration, and reduces the risk of part failure mid-field.
Monitoring and Adjusting Gearbox Oil
The gearbox is the heart of a John Deere rotary cutter, transferring power from the PTO shaft to the blades. Monitoring gearbox oil is critical for long life.
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Check Oil Level: Inspect the sight glass or remove the level plug. Oil should sit at or just below the fill hole.
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Top Off When Needed: Add the correct grade of gear oil (usually 80W-90 or equivalent) if the level is low.
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Look for Contamination: Milky oil indicates water intrusion, while metallic shavings suggest internal wear.
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Change Oil Seasonally: At minimum, replace gearbox oil once per year. More frequent changes are wise if you mow in heavy brush or wet conditions.
👉 Low or contaminated oil is the number one cause of John Deere gearbox noise issues and premature failures. Regular checks protect your mower’s most expensive component.
Inspecting the PTO Shaft, Bearings, and Seals
The PTO shaft is under constant stress, and any failure here will halt mowing instantly. Inspect it regularly:
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Check U-Joints: Rotate the shaft by hand and feel for roughness or play. Replace cross bearings at the first sign of wear.
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Inspect Shields: Ensure PTO guards are intact and free of cracks. Replace damaged shields immediately for safety.
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Examine Splines: Look for wear or rounding on input and output splines. Worn splines can cause slippage under load.
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Oil Seals: Inspect gearbox input and output seals. If you see oil leakage, replace seals before the gearbox loses significant fluid.
A healthy PTO shaft keeps power flowing smoothly to the mower, preventing costly downtime in the middle of mowing season.
Seasonal Maintenance: Pre-Season and Post-Season
Your mower’s performance depends heavily on how you prepare it before and after each mowing season.
Pre-Season Checklist:
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Inspect blades for sharpness, chips, or cracks. Replace or sharpen as needed.
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Check stump jumper for bends or cracks.
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Verify PTO shaft length and alignment.
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Top off gearbox oil and grease all points.
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Tighten all fasteners to spec.
Post-Season Checklist:
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Clean the deck thoroughly to prevent rust.
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Drain and replace gearbox oil before storage.
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Grease all zerks to push out moisture.
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Store the mower in a dry, covered location to reduce corrosion.
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If storing outdoors, cover the gearbox and PTO shaft with moisture-resistant wraps or caps.
👉 Seasonal care is the best insurance against surprise repairs and ensures your mower is ready when the next cutting season begins.
Why Preventative Maintenance Matters
Neglecting small tasks—like checking gearbox oil or tightening blade bolts—can quickly lead to expensive failures. For example:
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A $15 neglected seal can lead to a $500 gearbox replacement.
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Loose blade bolts may cause deck cracks that require welding or full panel replacement.
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Dry bearings eventually seize, damaging spindles and halting your operation.
By dedicating a short amount of time to preventative checks, you can avoid the high costs of emergency downtime.
Where to Find Replacement Parts
Even with the best care, wear parts eventually need replacement. At Fimic Implement, we provide a full range of John Deere-compatible parts designed to keep your MX series mower running at peak efficiency. Whether you need a replacement gearbox, a PTO shaft, new oil seals, or rotary mower blades, our aftermarket components are engineered to fit John Deere models at a fraction of OEM pricing.
Browse our full selection of John Deere rotary mower parts here.
Final Thoughts
Properly maintaining your John Deere rotary mower isn’t complicated—it’s about consistency. By greasing key points, tightening bolts, monitoring gearbox oil, and preparing your equipment for the season, you’ll dramatically extend the lifespan of your mower.
Whether you’re running an MX5 on small pastures or an MX10 on large acreage, maintenance ensures reliable performance and lower operating costs. Combine these habits with quality replacement parts, and your mower will deliver clean, powerful cuts year after year.