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Why the Rear Final Gear Decides the Health of Your Whole Drivetrain

The rear differential final gear is the mechanical junction where torque leaves the driveshaft and reaches the rear axles. On the Honda Foreman 500 (TRX500) platform, that junction absorbs extreme shock loads every time you tow a heavy load or push hard through rough trail sections. Every bit of pulling power your engine makes passes through this one set of teeth before it reaches the ground.

When the gear teeth wear or pit, the damage does not stay contained. Play grows, mesh quality drops, and the wear spreads into bearings, splines, and axles. Replacing a worn final gear is not just about restoring movement — it is about preserving the integrity of your entire drivetrain before one small part takes out the whole rear end.

Featured Part: 2017-2019 Foreman 500 Rear Differential Final Gear

Engineered to exact OEM tolerances, the Fits 2017-2019 Honda Fourtrax Foreman 500 Rear Differential FINAL GEAR serves as a direct-fit replacement for Honda part 41300-HR3-W50. The unit features reinforced gear teeth that resist pitting under heavy-duty farm and utility use — the exact load pattern that kills the stock gear on working machines.

Before you order, review the full fitment list, machining details, and warranty terms on the Fits 2017-2019 Honda Fourtrax Foreman 500 Rear Differential FINAL GEAR product page. Two minutes there shows you the gear matches your exact model year and axle configuration, and saves you the cost of a return shipment.

View Technical Details & Compatibility

Technical Specifications and Compatibility

Every figure below comes straight from the product data. Check the fitment row against your machine before you pull the rear end apart.

Two fitment points matter most. First, this gear covers both the Foreman 500 and the Rancher 420 across the 2017-2019 range. Second, it is built for Solid Rear Axle (SRA) configurations only — IRS models use a different differential layout and need a different part altogether.

Match the OEM number 41300-HR3-W50 against the number on your old gear or your parts diagram before you buy. If the numbers differ, stop and check the related gears further down this page instead of forcing a fit.

Four Early Warning Signs of Final Gear Failure

Differential failure rarely happens instantly. The assembly warns you first, and catching those warnings early is the difference between a planned weekend repair and a complete axle lock-up out on the trail. Watch for these four symptoms:

• High-pitched gear whine: often caused by improper gear meshing or worn pinion bearings. If the noise changes with speed, the mesh is your first suspect.
• Metal shavings in the oil: during a fluid change, look for glitter or metallic flakes in the drained oil. That sparkle indicates gear tooth pitting.
• Backlash clunk: a noticeable clunk when you shift from Neutral to Drive or Reverse suggests excessive play between the ring and pinion.
• Leaking pinion seal: differential fluid on the rear of the case means lubrication is dropping — and running low leads to eventual gear burning.

Find any one of these on your machine? Plan the replacement now, on your schedule, instead of waiting for the rear axle to seize in the middle of a job.

Installation Best Practices That Keep Your 1-Year Warranty Valid

Replacing the final gear takes mechanical precision. Work through these four steps in order and you protect both the new part and your 1-year warranty coverage:

1. Thorough case cleaning: make sure the differential housing is completely free of old metal fragments and sludge before the new gear goes in. Leftover debris chews through fresh teeth fast.
2. Check the axle splines: inspect the rear axle splines for wear. A new differential paired with worn axle splines is a guaranteed premature failure.
3. Replace the seals: always fit new O-rings and dust seals during reassembly to prevent water intrusion into the case.
4. Respect the break-in period: for the first 5-10 hours of operation, avoid extreme towing so the gear teeth can mate correctly.

Each step targets a specific failure mode that kills rebuilt differentials: debris contamination, spline wear, water intrusion, and overloaded break-ins. Skip one and you will likely be back inside the case within a season.

Need a Final Gear for a Different Foreman 500 Year or Trim?

Koeep stocks matching rear final drive gears across the wider Foreman 500 lineup, so older machines can get the same fix.

2008-2011 Foreman 500 EPS

Servicing the earlier power-steering generation? The Fits Honda FourTrax Foreman 500 EPS 2008-2011 Rear Final Drive Differential Gear covers that model range, so a 2008-2011 EPS rebuild uses the same direct-fit approach as the newer machines.

2014-2019 Foreman 500 ES and EPS

For the ES and EPS trims of that era, use the Fits 14-19 Honda FourTrax Foreman 500 ES EPS Rear Final Drive Differential Gear. It targets the 2014-2019 ES and EPS variants specifically, which prevents fitment surprises at install time.

Rancher 420 Owners

Running a Rancher instead of a Foreman? Our Ultimate Guide: Honda FourTrax Rancher 420 ES 2X4 (2014-2019) Rear Final Gear Differential covers replacement steps, specs, and FAQ for that machine.

For everything else in the driveline — gears, bearings, seals, and shafts — browse the full Transmission & Drivetrain Parts collection on Koeep.

Not Sure Which Gear Fits? Talk to Us First

Fitment mistakes cost you downtime, so check with us before you order. Send your model, year, and axle type through the request-for-quote page, email support@koeep.com, or message the team directly on WhatsApp. A quick photo of your differential tag or old part is usually enough to verify the match before money changes hands.

Technical FAQ

The questions below come up most often from 2017-2019 Foreman 500 and Rancher 420 owners replacing the rear final gear.