Yukon Gear & Axle - User Manual

Yukon Gear & Axle
Ultimate 88 Axle Kit Installation Manual
© COPYRIGHT 2011 - Yukon Gear & Axle
PLEASE READ COMPLETELY BEFORE INSTALLATION

Summary

Parts List

Required Tools

Installation

Prepare Axle Housing

Cut axle housing ends flush with the shoulder and de-burr.

Install Bearing Seats

Press bearing seats onto housing with the flat side up.

Attach Retainer Plates

Install retainer plates using bolts and nuts, torque to spec.

Install Axle Shafts

Assemble bearings and seals, then slide axle shafts into the housing.

Install Brake Components

Install brake rotors, calipers, and mount wheels and tires.

Final Differential Steps

Re-install the differential cover and fill with gear oil.

Warranty Information

Overview

1. Function Description
2. Important Technical Specifications
3. Usage Features
4. Maintenance Features
5. Required Tools for Installation
6. Warranty Information

This document is an installation manual for the Yukon Gear & Axle Ultimate 88 Axle Kit, designed to enhance the functionality of a Ford 8.8 rear axle by eliminating C-clips and widening the axle by approximately 0.96 inches on each side. The kit is intended for use with a Ford 8.8 31-spline disc brake rear axle from a Ford Explorer.

Function Description:

The Yukon Ultimate 88 Axle Kit replaces the stock C-clip retention system with a bolt-in axle design, which is generally considered stronger and safer, especially in off-road or high-performance applications. By eliminating C-clips, the axle shafts are held in place by a bearing and retainer assembly pressed onto the shaft and then bolted to the axle housing. This design prevents the axle shaft from sliding out of the housing in the event of an axle shaft or bearing failure, a common concern with C-clip axles. The kit also includes new axle shafts that are double-drilled for both 5x4.5-inch and 5x5.5-inch bolt patterns, offering versatility for various wheel applications. The installation process involves modifying the existing axle housing by cutting the ends flush with the shoulder, pressing on new bearing seats, and then installing the new axle shafts with their integrated bearing and retainer assemblies.

Important Technical Specifications:

• Compatibility: Ford 8.8 31-spline disc brake rear axle from a Ford Explorer.
• Axle Widening: Approximately 0.96 inches per side.
• Axle Shaft Splines: 31-spline (implied by compatibility with 31-spline differential).
• Bolt Patterns: Double-drilled for 5x4.5 inches and 5x5.5 inches.
• Retainer Plate Bolts: 3/8-inch Grade C lock nuts, torqued to 40 ft. lbs.
• Wheel Studs: 1/2-inch studs, torqued to 90 ft. lbs.
• Materials: High-strength components, including Grade 8 bolts for the cross pin and Grade C lock nuts for the retainer plates, ensuring durability and reliability. The bearing and seal kit (AK SET20) is a critical component for proper function.

Usage Features:

The kit is designed for DIY installation, though it requires specialized tools like a hydraulic press and a grinder. The step-by-step instructions guide the user through the entire process, from preparing the vehicle and draining fluids to modifying the axle housing and installing the new components.

• Enhanced Safety: Eliminates C-clips, preventing axle shaft loss in case of failure.
• Increased Strength: Bolt-in design provides a more robust axle retention system.
• Wider Stance: Adds approximately 0.96 inches per side, potentially improving stability or accommodating wider tires.
• Versatile Wheel Fitment: Double-drilled bolt patterns (5x4.5" & 5x5.5") allow for a wider range of wheel choices.
• Comprehensive Kit: Includes all necessary components such as retainer plates, bearing seats, spacers, left and right rear axles, bearing and seal kits, and various bolts and nuts.
• Clear Instructions: The manual provides detailed, illustrated steps to facilitate installation.

Maintenance Features:

While the kit itself is a modification, proper installation and subsequent maintenance are crucial for its longevity and performance.

• Pre-Installation Cleaning: Emphasizes cleaning housing ends and threads to ensure proper fit and adhesion of thread-locking compounds.
• Lubrication: Requires axle grease for certain components and fresh gear oil for the differential after installation.
• Torque Specifications: Specific torque values are provided for critical fasteners (retainer plate nuts, wheel studs) to ensure secure assembly and prevent premature wear or failure.
• Thread Locking Compound: High-strength thread locking compound is recommended for wheel studs to prevent loosening.
• Silicone Sealant: Silicone is used on the recess of the bearing seats and seal areas to ensure a proper seal and prevent leaks.
• Regular Inspection: Although not explicitly stated as a maintenance feature of the kit itself, regular inspection of the axle assembly, including torque checks on critical fasteners, is implied for any modified drivetrain component.

Required Tools for Installation:

The installation requires a range of common and specialized tools:

• Safety Glasses, Jack and Jack Stands, Wheel Chocks
• Grinder, Cut off Wheel, Deburring Tool
• Torque Wrench, Appropriate Wrenches, Screwdrivers, Socket Set
• Shop Rags, Axle Grease, Gear Oil, Oil Catch Pan
• Hydraulic Press (essential for pressing bearings onto axles)

Warranty Information:

Yukon Gear & Axle provides a one (1) year warranty from the date of sale against defects in materials and workmanship for the Ultimate 88 Axle Kits. The warranty is contingent on proper installation and maintenance according to Yukon instructions and excludes damage from modification, accident, abnormal use (including off-road or competition use), or misuse. It is void if installed on vehicles with tires exceeding Yukon's maximum recommended tire size. The warranty covers repair, replacement, or refund at Yukon's discretion for verified defects. It explicitly excludes incidental or consequential damages, labor charges, and damage caused by non-Yukon components.

Yukon Gear & Axle Specifications