AE86 OS Giken Super Lock 1.5-Way Limited Slip Differential (Corolla 1983-1987)

OS Giken Super Lock 1.5-Way Limited Slip Differential

For 1983–1987 Toyota Corolla AE86 4A-GE Manual Transmission Models with T-Series Rear Differential

Overview

The OS Giken Super Lock Limited Slip Differential is a premium mechanical clutch-type LSD for Toyota AE86 4A-GE applications. Designed to provide strong rear-wheel traction without the abrupt, noisy behavior associated with many conventional clutch-type differentials, the Super Lock combines low initial preload with smooth, progressive locking under power.

The standard AE86 configuration uses a 1.5-way 25/38 ramp design with 20 friction plates and can progressively reach full lock as drivetrain load increases. This provides predictable power delivery during corner exit, acceleration, spirited street driving, track use, and performance driving while retaining surprisingly civilized low-speed behavior.

Separate Zenki and Kouki configurations are available because early and late AE86 T-Series rear axles use different axle spline dimensions. Selecting the correct version for the vehicle's production date and actual rear axle configuration is critical.

Key Features

• Premium mechanical clutch-type limited slip differential
• 1.5-way standard configuration
• 25/38 ramp configuration
• 20 friction plates
• Progressive locking with up to full lock under load
• Low initial preload for smooth low-speed operation
• Designed to reduce chatter and abrupt engagement compared with more aggressively preloaded clutch LSDs
• Spline-through-side-gear design allows a high-capacity friction plate arrangement
• High-grade steel alloy construction
• Chemically heat-treated drivetrain components
• Raw-forged gears for increased strength
• Precision-machined clutch plates
• Billet-machined differential case
• Separate Zenki and Kouki versions for the correct AE86 axle configuration

Progressive Super Lock Design

The Super Lock differs from a conventional high-preload clutch LSD by using a pressure-ring and lock-timing system that allows relatively free differential action during light-load driving while progressively increasing lock as torque is applied.

This allows the differential to remain smooth and predictable during parking, low-speed turns, and normal street driving while delivering substantially stronger lock when accelerating out of a corner or applying power aggressively.

The high-capacity 20-plate arrangement distributes load across a greater friction area, helping provide consistent lock characteristics, durability, and heat management during repeated performance use.

Vehicle Fitment

Toyota Corolla Levin / Sprinter Trueno

• 05/1983–09/1985 Toyota Corolla Levin / Sprinter Trueno – AE86 Zenki – RWD – 4A-GE – Manual Transmission – T-Series Rear Differential
• 10/1985–04/1987 Toyota Corolla Levin / Sprinter Trueno – AE86 Kouki – RWD – 4A-GE – Manual Transmission – T-Series Rear Differential

Toyota Corolla Sport GT-S

• 1985 Toyota Corolla Sport GT-S – AE86 Zenki – RWD – 4A-GE – Manual Transmission – Early T-Series Rear Differential
• 1985–1987 Toyota Corolla Sport GT-S – AE86 Kouki – RWD – 4A-GE – Manual Transmission – Late T-Series Rear Differential, when equipped with the later production axle configuration

Fitment Notes

• For 4A-GE / 4AG manual-transmission AE86 applications
• Requires the factory-style T-Series rear differential configuration
• Does not fit the factory 4A-C / SR5 rear differential configuration
• Zenki and Kouki differential centers are not interchangeable with mismatched axle splines
• Zenki / early configuration applies to 05/1983–09/1985 production
• Kouki / late configuration applies to 10/1985–04/1987 production
• Early Zenki applications use the smaller 24 mm / 23-spline axle configuration
• Later Kouki applications use the larger 25.4 mm / 23-spline axle configuration
• Do not select solely by exterior Zenki/Kouki appearance if the rear axle has been swapped
• Verify the actual rear axle and production date before ordering
• Proper differential bearing preload, backlash, and ring-and-pinion setup are required during installation
• Professional differential installation is strongly recommended
• Use OS-250R V2 or another OS Giken-approved differential oil for proper break-in and locking performance

Product Specifications

Brand: OS Giken
Series: Super Lock
Product Type: Mechanical Limited Slip Differential
Position: Rear
Differential Type: Clutch-Type LSD
Configuration: 1.5-Way
Ramp Angles: 25/38
Total Friction Plates: 20
Lock Timing: 336
Preload: 10S
Locking Capability: Progressive Up to Full Lock
Construction: High-Grade Steel Alloy
Gear Construction: Raw-Forged
Component Treatment: Chemical Heat Treatment
Case Construction: Billet-Machined
Drivetrain: Rear-Wheel Drive
Engine Application: 4A-GE / 4AG
Transmission: Manual
Rear Differential: Toyota T-Series

Zenki vs. Kouki – Which Version Do You Need?

The Zenki / Early version is designed for AE86s produced from May 1983 through September 1985. These cars use the smaller early T-Series axle spline configuration.

The Kouki / Late version is designed for AE86s produced from October 1985 through April 1987 and uses the larger late T-Series axle spline configuration.

The two versions share the same 1.5-way Super Lock design, 20-plate clutch pack, 25/38 ramp configuration, lock timing, and preload specification. The difference is the axle-side fitment.

If the rear axle has ever been replaced or converted, select the LSD according to the actual axle configuration rather than the vehicle's model year or exterior appearance.

Available Configurations

Zenki / Early – 05/1983–09/1985 Production

• Early AE86 T-Series rear differential
• 24 mm / 23-spline axle configuration
• 1.5-way Super Lock LSD
• (1) Limited slip differential center

Kouki / Late – 10/1985–04/1987 Production

• Late AE86 T-Series rear differential
• 25.4 mm / 23-spline axle configuration
• 1.5-way Super Lock LSD
• (1) Limited slip differential center