Yukon YDGGM55P-17-1 Dura Grip LSD for GM 55P 8.2 Drop-Out 17-Spline 3.73 Down

Vehicle Fitment

• 1955-1964 Chevrolet Bel Air (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)
• 1958-1964 Chevrolet Impala (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)
• 1958-1964 Chevrolet Biscayne (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)
• 1956-1962 Chevrolet Corvette (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)
• 1959-1964 Chevrolet El Camino (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)
• 1962-1964 Chevrolet Chevy II (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)
• 1955-1961 Chevrolet Nomad (GM 55P 8.2" Drop-Out Rear Differential, 17-Spline)

Fitment Notes

• Fits the GM 55P 8.2" drop-out (3rd member) rear differential with 17-spline bolt-in axles ONLY - does not fit any other GM axle or housing type
• Compatible with 3.73 gear ratio and numerically lower carriers (3-series and below); also fits thick ring gear sets
• 1955-1956 special note: factory carriers with ribs on the back of the ring gear side (casting numbers ending in "306") are 4-series carriers - a new ring and pinion or ring gear spacer is required before installing this positraction unit
• Yukon recommends non-synthetic GL-5 gear oil with Yukon LSD additive (part# OILADD) for smooth, long-lasting operation - synthetic oil is NOT recommended and may cause chatter or noise
• This is a limited slip differential (positraction), not a locking differential - torque transfer is smooth and progressive, not lock-to-lock

Features

• High-strength nodular iron carrier case for superior rigidity and durability in classic car restoration and street/strip performance applications
• Forged 4320 chromoly steel spider gears provide significantly greater strength and wear resistance under high-torque conditions
• Raybestos composite clutch packs deliver smooth yet aggressive traction engagement - ideal for street driving and drag strip use alike
• Compatible with thick ring gear sets - provides broad versatility across the full range of available GM 55P gear ratios
• Fully rebuildable - clutch packs and internal components can be replaced for extended service life without full carrier replacement
• Assembled in the USA with extensive product testing and state-of-the-art engineering validation
• Provides street-friendly limited slip behavior appropriate for restored classics, street performance builds, and bracket racing
• Backed by Yukon's Y.E.S. Plan - lifetime no-questions-asked coverage for as long as you own the vehicle

Specifications

• Part Number: YDGGM55P-17-1
• Type: Dura Grip Positraction Limited Slip Differential (LSD)
• Axle Spline Count: 17
• Compatible Gear Ratios: 3.73 and numerically lower (also fits thick gears)
• Case Material: Nodular Iron
• Spider Gear Material: Forged 4320 Chromoly Steel
• Clutch Type: Raybestos Composite
• Differential Application: GM 55P 8.2" Drop-Out (3rd Member) Rear
• Assembly Location: USA
• Position: Rear Axle

Included Components

• 1x Assembled Dura Grip Limited Slip Differential Carrier

Product Description

The Yukon YDGGM55P-17-1 Dura Grip is a high-performance positraction limited slip differential built for the GM 55P 8.2" drop-out (3rd member) rear differential - the classic rear axle found in 1955-1964 Chevrolet passenger cars including the Bel Air, Impala, Biscayne, Corvette, El Camino, Chevy II, and Nomad. This is one of the most sought-after positraction upgrades for restorers and builders of 1950s and early 1960s GM vehicles, providing a factory-style limited slip experience that is appropriate for both street driving and bracket racing.

The Dura Grip is built around a high-strength nodular iron case with forged 4320 chromoly spider gears and Raybestos composite clutch packs. It is compatible with 3.73 and numerically lower ratios and also fits thick ring gear sets, giving it broad compatibility across the available GM 55P gear ratio lineup. An important fitment note for 1955-1956 vehicles: factory 4-series carriers with ribs on the back of the ring gear side (identifiable by casting numbers ending in "306") are not directly compatible - a new ring and pinion or ring gear spacer must be installed before this positraction unit can be used.

This unit is fully rebuildable, allowing clutch packs and internals to be serviced rather than requiring full carrier replacement. Always use non-synthetic GL-5 gear oil with Yukon's LSD additive (part# OILADD) during installation and service - synthetic oil can cause clutch chatter and premature wear. The GM 55P uses a drop-out 3rd member design, so the entire carrier assembly can be set up on a bench before installation into the housing. Pair with a compatible Yukon master overhaul kit for all necessary bearings and hardware.