PTO Shaft, 6 Spline Tractor, 1-3/8" PTO Drive Shaft, Series 4 Tractor PTO Shaft, 31.5"-41" Brush Hog PTO Shaft Orange for Finish Mower/Bush Hog Review

Overview

This PTO shaft is a Series 4 universal drive shaft designed to connect a 1-3/8", 6-spline tractor output to implements like brush hogs, finish mowers, and bush hogs. With an adjustable length from 31.5 to 41 inches, it’s built for compact and utility tractors in the 20-50 HP range, making it a solid replacement or upgrade for mowing tasks on small farms, hobby farms, or large residential properties. It’s not a mower itself, but the critical link that powers your mower—so getting it right matters.

Who Should Buy This

• Tractor owners with 20-50 HP compact or utility tractors – This shaft fits standard Category 1 and 2 hitches and common PTO spline sizes, making it a direct swap for worn or broken OEM shafts on many Kubota, John Deere, Mahindra, and similar models.
• Hobby farmers or landowners with brush hogs or finish mowers – If you’re mowing 2-10 acres of pasture, trails, or fields, this shaft handles the torque and length range needed for medium-duty rotary cutters and finish mowers.
• DIY mechanics who prefer a budget-friendly replacement – At $108.99, it’s often half the price of a dealer-branded shaft, so it appeals to those comfortable with basic tractor maintenance and looking to save money.
• Owners of older or orphaned mower decks – If your implement’s original shaft is rusted, bent, or missing, this universal fit can save you from buying a whole new mower.

Key Features Breakdown

• 1-3/8" 6-spline ends – This is the standard PTO output size on most compact tractors. It fits both the tractor side and most implement input yokes. If your tractor uses a different spline (like 1-1/8" or 21-spline), this won’t work—so double-check before buying.
• Series 4 rating – Series 4 shafts are rated for medium-duty applications, typically handling up to 40-50 HP at 540 RPM. That’s plenty for brush hogs cutting 4-6 foot swaths of grass and light brush, but not for heavy-duty tillers or large rotary cutters on 60+ HP tractors.
• Adjustable length: 31.5" to 41" – The telescoping design lets you match the shaft to your tractor’s PTO-to-implement distance. Proper length prevents binding (too short) or excessive overhang (too long), which can damage the tractor’s PTO seal. Measure from the tractor’s PTO stub to the implement’s input yoke, then add 2-3 inches for safety.
• Orange powder-coat finish – The bright orange coating isn’t just cosmetic; it resists rust and makes the shaft easy to spot in tall grass or muddy conditions. However, it can chip if you frequently drop the shaft on gravel or rocks.
• Includes shear bolt and guard – A shear bolt (typically 1/4" grade 2 or 5) protects the tractor’s PTO from shock loads if you hit a stump or rock. The plastic guard covers the rotating shaft, but it’s not a full driveline shield—you should still wear snug clothing and avoid loose sleeves.

Pros

1. Universal fit for most compact tractors – The 1-3/8" 6-spline ends and adjustable length cover a wide range of common setups, so it’s likely a drop-in replacement for many brands.
2. Budget-friendly price – At $109, it’s significantly cheaper than OEM shafts from tractor dealers, which can run $150-250 or more.
3. Quick length adjustment – The telescoping inner and outer tubes slide easily with a simple pull-pin or bolt system, so you can fine-tune fit in minutes without tools.
4. Shear bolt protection – The included shear bolt helps prevent expensive damage to your tractor’s PTO if you hit a hidden rock or stump. Spare bolts are cheap and easy to find.
5. Decent build quality for the price – Welds look clean, the splines are well-machined, and the orange coating adds a layer of corrosion resistance. It’s not heavy-duty, but it’s solid for medium use.
6. Lightweight enough for one-person install – At around 10-12 pounds, you can easily handle it alone without a helper or lifting equipment.

Cons

1. Not for heavy-duty or high-HP tractors – If your tractor is over 50 HP or you’re mowing thick brush, saplings, or overgrown fields, this Series 4 shaft may twist or fail. Upgrade to a Series 5 or 6 for serious abuse.
2. Guard is minimal – The plastic shield covers the yoke but leaves the telescoping tube exposed. For safety, you’ll want to keep your hands and clothing clear—it’s not a fully enclosed driveline.
3. Fit can be tight on some implements – The yoke dimensions might not match all older or non-standard brush hog input shafts. You may need to grind or shim the yoke for a perfect fit on some brands.
4. Shear bolt is a weak point (by design) – While it protects the tractor, it can break on moderate impacts like a buried rock or thick root. Carry spare bolts—they’re cheap but annoying to replace mid-job.

Bottom Line

If you own a compact tractor between 20 and 50 HP and need a reliable, affordable replacement PTO shaft for your brush hog or finish mower, this Series 4 shaft is a smart buy. It’s not built for commercial abuse or huge tractors, but for the typical hobby farmer or large-lot owner mowing a few acres of grass and light brush, it delivers solid performance at a price that won’t hurt. Measure your tractor’s PTO-to-implement distance carefully, and keep a few spare shear bolts on hand. I recommend it for budget-conscious owners who want a functional, no-frills replacement—just don’t expect it to outlast a premium OEM shaft on heavy-duty work.

Frequently Asked Questions

Q: Will this fit my John Deere 1025R or Kubota B2601?
A: Yes, both of those compact tractors use a 1-3/8" 6-spline PTO. Just measure the distance from your tractor’s PTO stub to your implement’s input yoke. The 31.5-41 inch range covers most setups, but measure to be sure—especially if you have a quick-hitch or offset implement.

Q: Can I use this on a 60 HP tractor with a 7-foot brush hog?
A: Not recommended. The Series 4 rating tops out around 50 HP. On a 60 HP tractor, you risk twisting the shaft or