Yukon Gear 4.56 Ring & Pinion Gear Set | Toyota 8" 4-Cylinder 4WD (1984-95 4Runner / 1979-95 Pickup)
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Yukon Gear 4-Cylinder 4.56 Ring & Pinion Gear Set
For 1984–1995 Toyota 4Runner and 1979–1995 Toyota Pickup 4WD with Toyota 8" 4-Cylinder Differential
Overview
The Yukon Gear 4-Cylinder 4.56 Ring & Pinion Gear Set is a differential gearing upgrade for classic Toyota 4WD applications equipped with the standard Toyota 8-inch 4-cylinder differential.
The 4.56:1 ratio provides increased mechanical advantage compared with taller factory gearing while remaining numerically lower than 4.88 and 5.29 ratios. It is well suited to vehicles with moderately larger tires that still see regular street and highway use.
This gear set uses a 29-spline pinion. Many original Toyota 8-inch 4-cylinder differentials use 27-spline pinion hardware, so the appropriate 29-spline companion flange, pinion seal, and pinion nut are required when converting an original 27-spline differential. The Toyota 8-inch 4-cylinder differential was commonly used with 20R, 22R, and 22RE applications, but fitment should ultimately be determined by the installed third member.
Key Features
- 4.56:1 ring and pinion ratio
- Designed for the Toyota 8" 4-cylinder differential
- 8.0-inch ring gear diameter
- Heavy-duty 29-spline pinion
- 10 ring gear bolts
- High-grade steel ring and pinion construction
- Gear-tooth surface finish designed to reduce friction and heat
- Fits the front and rear Toyota 8-inch applications listed below
- Available with or without 27-to-29 spline conversion hardware
- Professional differential setup required
Toyota 8" 4-Cylinder Differential Identification
Toyota used different 8-inch third-member designs across these vehicles, so identifying the installed differential before ordering is important.
Standard 4-Cylinder Toyota 8" Differential
- Typically has three external reinforcement ribs
- Commonly used with 20R, 22R, and 22RE applications
- Uses the standard Toyota 8-inch 4-cylinder ring and pinion configuration
- Uses this gear set
V6 / Turbo Toyota 8" Differential
- Uses a different third-member and ring-and-pinion configuration
- Typically has additional reinforcement and a distinctive upper rib
- Commonly associated with 22R-TE Turbo and 3VZ-E V6 applications
- Requires the separate V6/Turbo gear set
Because Toyota third members are frequently swapped between vehicles, verify the actual differential installed rather than relying solely on engine type.
Toyota 8" Differential Identification
Toyota used different 8-inch third-member designs across these vehicles, so identifying the installed differential before ordering is important.
Standard 4-Cylinder Toyota 8" Differential
- Commonly found in 20R, 22R, and 22RE applications
- Typically identified by three external reinforcement ribs
- Uses this 4-cylinder-style ring and pinion gear set
V6 / Turbo Toyota 8" Differential
- Typically identified by four reinforcement ribs and a trapezoid-shaped upper rib
- Commonly associated with 22R-TE and 3VZ-E applications
- Uses the separate V6/Turbo-style gear set
Because Toyota 8-inch third members are frequently swapped between vehicles, verify the actual differential installed rather than relying solely on engine type.
Vehicle Fitment
4WD models with the Toyota 8-inch 4-cylinder differential only.
Toyota 4Runner
- 1984–1985 Toyota 4Runner – 1st Gen – Toyota 8" 4-Cylinder Differential – Front & Rear
- 1986–1989 Toyota 4Runner – 1st Gen – Toyota 8" 4-Cylinder Differential – Rear Only
- 1990–1995 Toyota 4Runner – 2nd Gen – Toyota 8" 4-Cylinder Differential – Rear Only
Toyota Pickup
- 1979–1983 Toyota Pickup – 1st Gen – Toyota 8" 4-Cylinder Differential – Front & Rear
- 1984–1985 Toyota Pickup – 2nd Gen – Toyota 8" 4-Cylinder Differential – Front & Rear
- 1986–1988 Toyota Pickup – 2nd Gen – Toyota 8" 4-Cylinder Differential – Rear Only
- 1989–1995 Toyota Pickup – 3rd Gen – Toyota 8" 4-Cylinder Differential – Rear Only
Fitment Notes
- Toyota 8-inch 4-cylinder differential required
- 4.56:1 gear ratio
- 29-spline pinion
- Factory 27-spline configurations require a compatible 29-spline companion flange, pinion seal, and pinion nut
- Front application is limited to 1979–1985 solid-front-axle 4WD models
- Does not fit the Toyota 7.5-inch IFS front differential used beginning in 1986
- Does not fit the Toyota 8-inch V6/Turbo third member
- On 4WD vehicles, front and rear differential ratios must match before engaging four-wheel drive
- Verify the installed third member on vehicles with axle or differential swaps
- Professional installation and differential setup are required
- Correct pinion depth, bearing preload, backlash, and gear contact pattern must be established during installation
- Proper ring-and-pinion break-in should be completed after installation
Product Specifications
Brand: Yukon Gear & Axle
Product Type: Ring & Pinion Gear Set
Differential: Toyota 8" 4-Cylinder
Gear Ratio: 4.56:1
Ring Gear Diameter: 8.0 Inches
Pinion Spline: 29-Spline
Ring Gear Bolts: 10
Material: High-Grade Steel
Drivetrain: 4WD
Front Application: 1979–1985 Solid Axle
Rear Application: 1979–1995 Toyota 8" 4-Cylinder Differential
Installation: Professional Differential Setup Required
Choosing 4.56 vs. 4.88 vs. 5.29 Gears
Gear-ratio selection should account for tire diameter, tire and wheel weight, transmission, permanent vehicle weight, highway use, terrain, and future tire plans. Larger or heavier tires reduce effective gearing, while bumpers, winches, sliders, skid plates, recovery gear, spare-tire carriers, roof racks, tools, and camping equipment increase the load the drivetrain must move.
The ranges below are Preserve Rad selection guidance for 4-cylinder Toyota 4WD builds rather than hard fitment limits. Two vehicles with the same tire diameter can benefit from different gearing when their transmissions, wheel/tire weights, permanent equipment, terrain, or highway usage differ.
Gear Ratio Selection Guide
| Gear Ratio | Best Tire Range | Typical Sweet Spot | Added Equipment | Best Use | What to Expect |
|---|---|---|---|---|---|
| Yukon 4.56 | 30–32 in. | 31 in. | Stock to lightly modified; approximately 0–200 lb of permanent added equipment | Daily driving, highway use, light trail use | Balanced cruising RPM and acceleration; mildest gearing of these three ratios |
| Yukon 4.88 | 32–34 in. | 33 in. | Moderately equipped; approximately 200–500 lb of permanent added equipment | Mixed street/trail use, hills, moderate overland builds | Strong all-around choice for 33-inch tires with more mechanical advantage than 4.56 |
| Yukon 5.29 | 34–36+ in. | 35 in. | Heavily equipped; approximately 500+ lb, or a particularly heavy wheel/tire package | Trail use, mountain driving, heavy overland builds, low-speed use | Most mechanical advantage of these three ratios, with higher highway engine RPM |
Tire Size & Vehicle Weight Guide
| Tire Size | Light / Near-Stock Build | Moderately Equipped | Heavy / Trail-Focused Build |
|---|---|---|---|
| 30–31 in. | 4.56 | 4.56 | 4.88 |
| 32 in. | 4.56 | 4.88 | 4.88 |
| 33 in. | 4.88 | 4.88 | 4.88–5.29 |
| 34 in. | 4.88 | 4.88–5.29 | 5.29 |
| 35 in. | 5.29 | 5.29 | 5.29 |
| 36–37 in. | 5.29 | 5.29 | 5.29 |
Tire weight matters, not just diameter. A heavy mud-terrain tire on a steel wheel places more demand on the drivetrain than a lighter tire and wheel combination of the same diameter because the drivetrain must accelerate additional rotating mass.
Permanent vehicle weight can justify deeper gearing. Steel bumpers, winches, armor, sliders, skid plates, spare-tire carriers, tools, recovery equipment, camping gear, and other permanently carried equipment increase the load the engine must move. The weight ranges above are general selection guidance rather than fixed cutoffs.
Transmission and highway use matter. Automatic-transmission trucks and vehicles that spend substantial time climbing grades or carrying weight may favor deeper gearing sooner, while a lighter manual-transmission truck that spends most of its time at highway speed may favor the less aggressive ratio when tire size allows.
Future tire size matters. If a truck is currently on 33-inch tires but is being built around a planned move to 35-inch tires, choosing 5.29 gears can make more sense than gearing only for the current tire size and paying for another differential setup later.
Available Configurations
29-Spline Gears Only (Requires Conversion Hardware)
- (1) Yukon 4.56 Ring Gear
- (1) Yukon 4.56 Pinion Gear
- For differentials already equipped with the required 29-spline pinion hardware
29-Spline Gears + 27-to-29 Spline Conversion Hardware Kit
- (1) Yukon 4.56 Ring Gear
- (1) Yukon 4.56 Pinion Gear
- (1) 29-Spline Companion Flange / Yoke
- (1) Pinion Seal
- (1) 29-Spline Pinion Nut
- Provides the pinion hardware required to convert factory 27-spline configurations