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Yukon Gear YPKF9-P-31-4 is a replacement spider gear and differential internal kit for compatible Ford 9-inch Trac-Lok positraction carriers with 31-spline axles. The 4-pinion design provides the internal gears and related hardware needed to replace worn or damaged carrier components while retaining the existing serviceable limited-slip carrier.
The kit includes two 31-spline side gears, four pinion gears, a cross-pin shaft, roll pin, and spider gear thrust washers. It is intended for differential repair, restoration, and carrier rebuilding when the spider gears or supporting internal components require replacement.
YPKF9-P-31-4 is designed for compatible 31-spline Ford Trac-Lok applications and does not include clutch plates. Its 4-pinion configuration makes it a focused replacement solution for servicing the internal gear set separately from the clutch pack.
Key Features & Specs:
Product Type: Differential spider gear / internal gear kit
Differential Fitment: Ford 9"
Axle Spline Count: 31-spline
Differential Type: Trac-Lok positraction / limited-slip
Design: 4-pinion
Side Gears: 2
Pinion / Spider Gears: 4
Cross-Pin Shaft: Included
Roll Pin: Included
Spider Gear Thrust Washers: Included
Clutches: Not included
Position: Rear
Service Use: Differential carrier rebuilding and internal gear replacement
Brand: Yukon Gear & Axle
Part Number: YPKF9-P-31-4
UPC: 883584160267
Proxy Number: 16026
Fitment:
Ford 9" Trac-Lok positraction
31-spline axle applications
4-pinion carrier configuration
Select Ford Mustang, Bronco, F-100, F-150, Fairlane, Falcon, Galaxie, Gran Torino, LTD, Maverick, Ranchero, and Thunderbird applications
Select Ford Econoline and E-Series van applications
Select Lincoln Continental and Mark III applications
Select Mercury Cougar, Comet, and Grand Marquis applications
About Yukon Gear Trac-Lok Spider Gear Kits:
Yukon Gear & Axle Trac-Lok spider gear kits provide replacement internal differential components for compatible Ford limited-slip carriers. Kits such as YPKF9-P-31-4 combine side gears, pinion gears, cross-pin hardware, and thrust washers for servicing worn or damaged carrier internals while retaining a usable differential assembly. They are suitable for restoration, performance, truck, van, and general drivetrain repair involving the correct Ford 9-inch Trac-Lok configuration.
