AD-21-6A Male Female Adapter 1.375" 21 Inner Spline 1.75" 6 Outer Spline for PTO
AD-21-6A Male Female Adapter 1.375" 21 Inner Spline 1.75" 6 Outer Spline for PTO
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AD-21-6A Male Female Adapter 1.375" 21 Inner Spline 1.75" 6 Outer Spline for PTO

Aftermarket
AD-21-6A
In stock
$53.55
The AD-21-6A Male Female Adapter is engineered to bridge different PTO shaft configurations with precision and...
$53.55

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AD-21-6A Male Female Adapter 1.375" 21 Inner Spline 1.75" 6 Outer Spline for PTO

The AD-21-6A Male Female Adapter is engineered to bridge different PTO shaft configurations with precision and reliability. Featuring a 1.375" (1 3/8") inner bore with 21 splines and a 1.75" (1 3/4") outer shaft with 6 splines, it ensures smooth power transfer between mismatched driveline components. Built from high-strength steel and treated with a corrosion-resistant finish, this adapter provides long-lasting durability even in harsh agricultural and industrial environments. Its secure, easy-to-install design makes it the perfect choice for adapting PTO systems and extending equipment versatility.

Adapt your PTO system with confidence — the AD-21-6A ensures smooth power transfer between 21-spline and 6-spline shafts with unmatched durability.

Features and Benefits

  • Converts 1.375" (21-spline female) to 1.75" (6-spline male) PTO connection

  • Heavy-duty steel construction for superior strength

  • Corrosion-resistant finish for long service life

  • Designed for tractors, farm implements, and industrial equipment

  • Ensures smooth and efficient torque transfer

  • Quick and secure installation for reliable use

Technical Specifications

Specification Value
Part Number AD-21-6A
Brand Aftermarket
Part Type Male-Female PTO Adapter
Inner Splines Count 21
Inner Spline Diameter 1.375 in (34.9 mm)
Outer Splines Count 6
Outer Spline Diameter 1.75 in (44.4 mm)
Length 6.81 in (173 mm)
Female End 1.375 in (21 splines)
Male End 1.75 in (6 splines)
Material Steel
Warranty 1 Year

 

Vehicle Compatibility

Equipment Type Application
Tractors PTO driveline conversion (21-spline to 6-spline)
Agricultural Equipment Farm implements, mowers, balers, harvesters
Industrial Equipment PTO-driven machinery with mismatched shaft sizes
General PTO Systems Adapts between 1 3/8" 21-spline female and 1 3/4" 6-spline male shafts

 

What's Included

  • 1x AD-21-6A Male-Female PTO Adapter (21 inner spline x 6 outer spline)

REVIEWS

JD

Exactly what I needed for my tractor PTO conversion. Fits perfectly and feels very solid. Made connecting my mower a breeze.

John D.

Boise, ID

★★★★★
SM

Great quality adapter. Installed in minutes and has been holding up well under heavy use on my baler. Highly recommend.

Steve M.

Lexington, KY

★★★★★
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Effective Date: October 2024
We offer a 30-day return policy, allowing you to request a return within 30 days of receiving your item. To qualify for a return, the item must be in its original condition—unused, with tags, and in its original packaging. A receipt or proof of purchase is also required.

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Possible return locations include:
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