Merchant Automotive Maximum Allison Transmission Pro Series DIY Kit, LLY| 2004.5 - 2005

LLY Pro Series Transmission Kit
Fits 2004.5–2005 GM LLY Duramax with Allison 1000 5-Speed

Built for power, tuned for performance — the Pro Series Transmission Kit for the 2004.5–2005 LLY Duramax is engineered for trucks running aftermarket tuning, upgraded fuel systems, and heavy-duty use. Whether you're towing, racing, or daily driving with increased horsepower, this kit transforms your Allison 1000 5-speed into a transmission that’s built to hold serious torque and deliver consistent performance.

This kit includes high-energy GPZ frictions, upgraded steels, reinforced pistons, and pressure plates — all selected to increase clutch capacity, improve shift response, and withstand the demands of a modified powertrain.

Key Benefits

• Designed for LLY Duramax trucks with performance upgrades
• GPZ frictions and heavy-duty steels provide improved holding power
• Molded clutch pistons and reinforced return springs ensure long-lasting performance
• Includes overhaul and calibration components for a full, reliable rebuild
• Features Merchant Automotive’s Deep Pan Kit with exclusive Deep Filter Lock

Kit Contents

Clutch Pack & Friction Materials

• GPZ187 C1 Friction, Internal Spline x8
• GPZ192 C1 Friction, External Spline x8
• GPZ175 C2 Friction x7
• GPZ196 C3/C4 Friction x12
• C5 High Energy Friction x6
• C2 Steel  x8
• C3/C4 Steel x10
• C5 Steel x6
• C1 Alto Apply Plate 
• C1 Alto Top Pressure Plate 
• C3 Pressure Plate
• C3/C4 Apply Plate x2
• C3/C4 Molded Piston (LML/L5P-style) x2
• Allison 1000 C3/C4 Piston Return Spring x2
• P1 Planet Shim
• C1 Molded Clutch Balance Piston (5-Speed)
• C2 Molded Clutch Balance Piston (5-Speed)

Transmission Internals

• Allison 5-Speed Overhaul Kit
• Allison T2 Bearing
• Allison 1000 T3–T5 Bearing x2
• Allison T4 Bearing
• Allison 1000 Front Pump Bushing
• Allison Stator Support Bushing
• Allison 1000 T1 & T6 Bearing x2
• Transfer Case to Transmission Adapter Gasket
• Pipe Thread Sealant Tape 
• Allison Cut Back Valve
• Allison 1000 P1 Drive Flange

Performance Upgrades & Tools

• Allison 1000 Deep Pan Kit with Merchant Automotive Deep Filter Lock
• PTO Billet Side Cover, Pro Series x2
• Transmission Pro Clutch Kit
• Transmission Sub Kit – LB7 A Kit
• TransGo Allison Shift Kit (5-Speed)
• Valve Body Kit 
• Allison Pressure Switch Assembly
• Transmission Pressure Regulator Spring Service Tool
• Trim Springs “A” & “B” x2
• F-Trim Sleeve
• Allison 1000 Pass Through Connector Body & O-Ring

This kit has been carefully curated for LLY owners who want dependable performance from their Allison under real-world stress. From hard pulls to tuned acceleration, the Pro Series Transmission Kit ensures your drivetrain stays ahead of the power curve.