Yukon Gear 4-Cylinder Master Differential Overhaul Kit (1979-85 4Runner/Pickup)

Yukon Gear 4-Cylinder Master Differential Overhaul Kit

For 1979–1985 Toyota Pickup & 1984–1985 Toyota 4Runner with 4-Cylinder Toyota 8" Rear Differential

Overview

The Yukon Gear 4-Cylinder Master Differential Overhaul Kit provides the bearings, races, seals, shims, and installation components required to properly rebuild the early Toyota 8-inch 4-cylinder rear differential found in 1979–1985 Toyota Pickup and 1984–1985 Toyota 4Runner applications.

Built around premium Timken bearings and races, this master kit is suitable for factory differential rebuilds, ring-and-pinion installations, and locker upgrades. Multiple configurations allow the kit to be matched to the installed 27- or 29-spline ring and pinion, 45mm or 50mm differential carrier, and either a conventional crush sleeve or solid pinion spacer.

Because these specifications are independent of one another, select each option based on the actual ring-and-pinion and differential carrier being installed.

Key Features

• Complete master overhaul kit for the early Toyota 8" 4-cylinder differential
• Premium Timken bearings and races
• Supports factory 27-spline and aftermarket 29-spline ring-and-pinion configurations
• Available for 45mm and 50mm carrier-journal configurations
• 45mm configuration supports the factory-style differential carrier and applicable 45mm-journal lockers
• 50mm configuration supports applicable ARB Air Locker, Yukon Zip Locker, and other 50mm-journal carriers
• Includes application-specific bearings, seals, shims, and differential setup components
• Choice of conventional crush sleeve or solid pinion spacer
• Suitable for differential rebuilds, gear-ratio changes, and locker installations

Configuration Guide

27-Spline – Factory Ring & Pinion

Select this option when rebuilding a differential that retains the factory-style 27-spline pinion.

29-Spline – Aftermarket Ring & Pinion

Select this option when using an aftermarket Toyota 8-inch ring-and-pinion set with a 29-spline pinion.

A 29-spline gear installation also requires the matching 29-spline pinion yoke, pinion seal, and pinion nut. These components are not included with this master overhaul listing and should already be included with or added to the selected 29-spline ring-and-pinion package.

45mm Carrier – OEM / 45mm-Journal Locker

Select the 45mm configuration when using the original-style Toyota 8-inch differential carrier or an aftermarket locker designed around the 45mm carrier-bearing journal.

50mm Carrier – ARB / Yukon Zip / V6-Style Locker

Select the 50mm configuration when installing an applicable 50mm-journal locker or differential carrier into the early Toyota 8-inch 4-cylinder third member. This configuration uses the appropriate larger-ID carrier bearings while retaining the early third-member bearing bore.

Standard Crush Sleeve

Uses the conventional crush-sleeve method for establishing pinion-bearing preload.

Solid Pinion Spacer Upgrade

Replaces the crush-sleeve setup with a solid spacer and shim-adjusted preload system.

Master Kit Contents

Depending on the selected configuration, the overhaul package includes the application-specific components required for the differential setup:

• Carrier bearings and races
• Pinion bearings and races
• Pinion seal
• Complete differential shim kit
• Ring gear bolts
• Pinion nut
• Crush sleeve or solid pinion spacer configuration
• Thread-locking compound
• Gear marking compound and application brush
• Differential gasket
• Application-specific installation components

Carrier bearings vary according to the selected 45mm or 50mm carrier configuration.

Vehicle Fitment

Toyota Pickup

• 1979–1980 Toyota Pickup – 1st Gen – 20R – 4-Cylinder Toyota 8" Rear Differential
• 1981–1983 Toyota Pickup – 1st Gen – 22R – 4-Cylinder Toyota 8" Rear Differential
• 1984–1985 Toyota Pickup – 2nd Gen – 22R / 22RE – 4-Cylinder Toyota 8" Rear Differential

Toyota 4Runner

• 1984–1985 Toyota 4Runner – 1st Gen – 22R / 22RE – 4-Cylinder Toyota 8" Rear Differential

Fitment Notes

• Toyota 8" 4-cylinder rear differential only
• Designed around the early Toyota 8-inch differential configuration
• Select 27-spline for the factory-style ring and pinion
• Select 29-spline when using the corresponding aftermarket ring-and-pinion configuration
• 29-spline yoke, seal, and pinion nut are not included with this overhaul kit
• Select 45mm Carrier for the OEM-style carrier or applicable 45mm-journal locker
• Select 50mm Carrier for applicable 50mm-journal ARB, Yukon Zip, or V6-style locker carriers
• Carrier-bearing journal size and pinion spline count are separate specifications
• Does not fit Toyota V6/Turbo-style 8" third members with an 83mm carrier-bearing bore
• Does not fit Toyota 7.5" differentials
• Toyota third members are commonly swapped; verify the installed differential before ordering
• Proper bearing preload, ring-and-pinion backlash, and gear contact pattern must be established during installation
• Professional differential setup is recommended

Product Specifications

Brand: Yukon Gear & Axle
Product Type: Master Differential Overhaul Kit
Differential: Toyota 8" 4-Cylinder
Position: Rear
Bearing Type: Tapered Roller
Bearing Brand: Timken
Pinion Options: 27-Spline / 29-Spline
Carrier Journal Options: 45mm / 50mm
Pinion Preload Options: Crush Sleeve / Solid Pinion Spacer
Installation: Professional Differential Setup Recommended

Available Configurations

Pinion Spline Configuration

• 27-Spline (Factory Ring & Pinion)
• 29-Spline (Aftermarket Ring & Pinion)

Carrier Bearing Configuration

• 45mm Carrier (OEM / 45mm-Journal Locker)
• 50mm Carrier (ARB / Yukon Zip / V6-Style Locker)

Pinion Spacer Configuration

• Standard Crush Sleeve
• Solid Pinion Spacer Upgrade