AM100979 PTO Clutch Replacement for John Deere STX38 Yellow Deck | Replaces AM122969, 5215-35

Overview

This AM100979 PTO clutch replacement is an aftermarket electric PTO clutch for select John Deere STX38 yellow deck, STX30, and related John Deere lawn tractor applications using the AM100979 / Warner 5215-35 clutch path.

Important STX38 fitment warning: This clutch is for select John Deere STX38 yellow deck applications. It is not the correct clutch for STX38 black deck or STX46 black deck models unless your original clutch number matches one of the replacement numbers listed below.

This clutch replaces John Deere AM100979, AM115090, AM118969, and AM122969, and cross-references Warner 5215-35 and Xtreme X0407.

Built with a 1-inch crankshaft bore, 5.50-inch pulley diameter, counter-clockwise rotation, and a 105 ft-lb torque rating, this clutch is designed to restore reliable mower deck blade engagement when matched to the correct original clutch number, deck color, pulley size, rotation, connector style, and product photos.

If you are comparing STX deck versions or diagnosing blade engagement problems, see our John Deere STX PTO clutch replacement guide.

Key Features

• Aftermarket electric PTO clutch replacement for listed John Deere yellow deck STX applications
• Crankshaft Bore: 1"
• Pulley Diameter: 5.50" / 5-1/2"
• Rotation: CCW from pulley side
• Voltage: 12V DC
• Torque Rating: 105 ft-lbs
• Belt Width: 1/2" or 5/8" belt compatibility on supported applications
• Connector Style: connector style as shown in product photos
• Encapsulated electromagnetic coil for reliable blade engagement
• Fully assembled and ready to install after fitment verification

Compatible Brands & Models

This PTO clutch fits select John Deere lawn tractor applications using the AM100979 / Warner 5215-35 clutch path.

• John Deere STX38: select yellow deck applications
• John Deere STX30: select applications using the AM100979 clutch path
• John Deere 108, 111, 112-L, 116, 120, 130, 160, 165, 170, 175: verify original clutch number before ordering

Fitment note: If your mower is an STX38 black deck or STX46 black deck, do not rely on the STX model name alone. Black deck STX38 and STX46 tractors commonly use a different clutch path.

Shopping for the black deck version? See the John Deere STX PTO clutch replacement guide to compare Yellow Deck, early Black Deck, and later Black Deck clutch paths.

Replaces OEM Part Numbers

• John Deere: AM100979, AM115090, AM118969, AM122969

Aftermarket Cross-Reference Numbers

• Warner: 5215-35, 521535
• Xtreme: X0407

What’s Included

• Complete electric PTO clutch assembly
• Factory-balanced 5.50" pulley
• Pre-installed bearing assembly
• Encapsulated electromagnetic coil
• Connector style as shown in product photos

Why Buy From PTO Direct USA?

• Fast USA shipping
• Fitment Guarantee
• 1-year warranty
• Fitment-first product support
• Clear product images for easier clutch identification
• Trusted replacement supplier for homeowners, repair shops, and mower service professionals

FAQ

Does this PTO clutch fit every John Deere STX38?

No. The John Deere STX38 has different clutch paths depending on deck color, serial range, and original clutch number. This AM100979 listing is for select STX38 yellow deck applications. Black deck STX38 tractors commonly use a different clutch path.

Is this the correct clutch for a yellow deck STX38?

Yes, this is the yellow deck STX38 clutch path when your original clutch number matches AM100979, AM115090, AM118969, AM122969, or Warner 5215-35.

Is this the correct clutch for a Black Deck STX38?

No. This AM100979 clutch is for select STX38 Yellow Deck applications. If your STX38 has a Black Deck, use the John Deere STX PTO clutch replacement guide to compare the early Black Deck and later Black Deck clutch paths before ordering.

Is this the correct clutch for an STX46?

No. This AM100979 clutch is not intended for typical STX46 Black Deck applications. STX46 fitment can vary by serial range and original clutch number. Use the John Deere STX PTO clutch replacement guide before ordering if you are comparing STX46 fitment.

What bore size does this clutch use?

This clutch uses a 1-inch bore. Confirm your crankshaft size before ordering.

What pulley diameter does this clutch use?

This clutch uses a 5.50-inch pulley diameter, also commonly described as 5-1/2 inches. Do not substitute a smaller 5.31-inch pulley clutch unless your original part number confirms that separate path.

What rotation does this clutch use?

This clutch uses counter-clockwise rotation, commonly written as CCW. Match rotation to your original clutch before installing a replacement.

Why does deck color matter on the STX38?

John Deere STX38 yellow deck and black deck tractors can use different PTO clutch paths. The deck color is an important fitment clue, but the original clutch number is still the most reliable way to confirm the correct replacement.

Can PTO Direct USA help me confirm STX38 fitment?

Yes. Email support@ptodirectusa.com with your mower model number, serial number, deck color, original clutch number, and clear photos of the old clutch. For STX38 tractors, include a photo showing whether the mower has a yellow deck or black deck.

For model-specific fitment help, see the STX38 PTO clutch replacement page.

Need help checking crankshaft size? Read the PTO clutch bore size guide.

Need help with rotation? Read the PTO clutch rotation guide.

If your old clutch will not come off the crankshaft, read the PTO clutch stuck on crankshaft guide before prying or hammering.

Need a different John Deere clutch? Browse the John Deere PTO clutch collection or the full electric PTO clutch catalog.