E-cowlboy Flywheel Locking Tool with 36mm 3/4’’ Socket for

E-cowlboy's flywheel locking tool with a forged 36mm 3/4” socket secures the flywheel so you can remove and reinstall the harmonic balancer on 6.6L Duramax engines with Allison automatics.

This heavy-duty kit is made to make crank pulley and harmonic balancer service faster and safer on Duramax diesels. Manufactured from corrosion-resistant CRV steel, the tool set fits into the transmission inspection opening to hold the flywheel teeth while you break or apply the nearly 300 ft-lb torque on the balancer bolt. It includes both a toothed engagement piece for pickup models and a toothed-and-screw variant for medium-duty trucks, plus a 36mm 12-point socket with a 3/4" drive for removal and re-torque operations.

How does this tool hold the flywheel without removing the starter?

The locking tool is designed to slip through the transmission inspection opening and engage the flywheel teeth directly, stabilizing the crankshaft while you work on the harmonic balancer. For pickups, a simple toothed plate indexes against the flywheel; for medium-duty trucks, the toothed plate with a hand-tightened bolt secures the engagement for heavier vibration and load.

• Slides through the inspection opening toward the engine to engage flywheel teeth.
• Toothed plate for 2500/3500 pickups inserts after removing the spring-loaded inspection plate.
• Toothed plate plus screw fits 4500/5500 trucks after removing the rubber inspection cap.
• Eliminates the need to remove the starter in many pump/balancer jobs.

Will the 36mm 3/4" socket handle the harmonic balancer bolt torque?

The included 36mm 12-point socket is forged for high torque applications and built to work with a 3/4" square drive breaker or torque wrench. It gives the correct fit for the Duramax harmonic balancer bolt and can also be used on axle nuts when needed.

• Forged 36mm 12-point socket for strong, repeated use.
• Fits 3/4" square drive tools for breaking and re-torqueing to spec.
• Multipurpose: compatible with some axle applications as well.

What materials and construction make this tool durable?

The main components are manufactured from chrome vanadium (CRV) steel, chosen for toughness, rust resistance, and long service life in workshop environments. Heat treatment and a properly machined tooth profile help the engagement pieces resist deformation under high torque.

• CRV steel construction for corrosion resistance and durability.
• Precision-cut teeth to engage flywheel without slipping.
• Forged socket for impact and torque resistance.

How do I know which engagement piece to use for my Duramax?

Vehicle application determines which version to use: 2500/3500 pickups use the toothed plate alone, while 4500/5500 trucks use the toothed piece with the hand-tightened screw for a more secure hold. Always remove the appropriate inspection cover before inserting the tool and confirm the tooth engagement visually before applying torque.

• 2500 / 3500: remove metal spring-loaded inspection plate; slide toothed piece in.
• 4500 / 5500: remove rubber inspection cap; insert toothed piece with screw and hand-tighten.
• Check engagement and alignment before breaking bolt torque.

Who is this for? Professional mechanics and competent DIYers who service 6.6L Duramax engines with Allison automatic transmissions will find this tool kit saves time and reduces disassembly. It's aimed at anyone needing a reliable method to lock the flywheel during harmonic balancer, crank pulley, or related front-end service on 2500–5500 series Duramax trucks. If you want a robust, corrosion-resistant toolset that fits inspection openings and accepts a 3/4" drive socket for high torque work, this E-cowlboy kit is built for that job.