Sumo Gear 4.7:1 Transfer Case Gear Set | RF1A (1985-95 4Runner / 1979-95 Pickup)

Sumo Gear 4.7:1 Transfer Case Gear Set For 1984–1995 Toyota 4Runner / 1979–1995 Toyota Pickup 4WD with RF1A gear-driven transfer case Overview The Sumo Gear 4.7:1 Transfer Case Gear Set is a low-range gearing upgrade for Toyota RF1A gear-driven transfer cases. It replaces the factory 2.28:1 low range with a 4.703:1 low range while retaining a 1.00:1 high range, providing substantially greater crawl control and torque multiplication without changing normal high-range gearing. The gears are precision machined in Japan from SCM420H alloy steel and are available in 21-spline and 23-spline configurations for factory RF1A applications, upgraded transfer cases, and properly configured dual-case drivetrains. Both configurations use the RF1A transfer case and the same 4.703:1 low-range ratio. Key Features 4.703:1 low-range ratio Retains 1.00:1 high range SCM420H alloy-steel gear construction Precision machined in Japan Available in 21-spline and 23-spline configurations Designed specifically for Toyota RF1A gear-driven transfer cases Suitable for single-case and properly configured dual-case drivetrains Low-Range Gearing & Spline Selection The 4.703:1 low-range ratio provides substantially deeper gearing for technical trails, rock crawling, and other low-speed off-road situations. High range remains 1.00:1, so highway and normal road gearing are unchanged. These gears fit Toyota RF1A gear-driven transfer cases only. They do not install into the factory chain-driven transfer cases used in other Toyota drivetrain configurations. 21-Spline — Naturally Aspirated 4-Cylinder RF1A Applications The 21-spline configuration is the factory-style setup used with most naturally aspirated 4-cylinder Toyota manual-transmission applications equipped with an RF1A gear-driven transfer case. Factory applications include: 1979–1980 Toyota Pickup 4WD — 20R with manual transmission and RF1A 1981–1995 Toyota Pickup 4WD — 22R / 22RE with manual transmission and RF1A 1984–1995 Toyota 4Runner 4WD — 22R / 22RE with manual transmission and RF1A For an otherwise stock naturally aspirated 4-cylinder Toyota equipped with its factory manual transmission and gear-driven RF1A transfer case, the 21-spline configuration is normally the correct selection. 23-Spline — 1986–1987 22R-TE Turbo / R151F Applications The stronger 23-spline RF1A configuration was used from the factory behind the R151F 5-speed manual transmission in 1986–1987 22R-TE turbo applications. Factory applications include: 1986–1987 Toyota Pickup 4WD — 22R-TE Turbo, R151F 5-speed manual 1986–1987 Toyota 4Runner 4WD — 22R-TE Turbo, R151F 5-speed manual The 23-spline configuration is also commonly used in dual-transfer-case systems, upgraded RF1A assemblies, and drivetrain conversions because of its larger input spline. Modified vehicles should be matched to the actual transfer-case input configuration rather than selected by model year alone. Important: Factory 3.0L 3VZ-E V6 applications use a chain-driven transfer case and are not directly compatible with these RF1A low-range gears. A V6 vehicle can use these gears only after conversion to a properly configured RF1A gear-driven transfer case. Vehicle Fitment 1984–1989 Toyota 4Runner – 1st Gen – 4WD – RF1A Gear-Driven Transfer Case 1990–1995 Toyota 4Runner – 2nd Gen – 4WD – RF1A Gear-Driven Transfer Case 1979–1983 Toyota Pickup – 1st Gen – 4WD – RF1A Gear-Driven Transfer Case 1984–1988 Toyota Pickup – 2nd Gen – 4WD – RF1A Gear-Driven Transfer Case 1989–1995 Toyota Pickup – 3rd Gen – 4WD – RF1A Gear-Driven Transfer Case Fitment Notes RF1A gear-driven transfer cases only 4WD applications only 21-spline: Most naturally aspirated 20R, 22R, and 22RE manual-transmission RF1A applications 23-spline: Factory 1986–1987 22R-TE / R151F manual applications Does not directly fit factory 3VZ-E V6 chain-driven transfer cases Automatic-transmission vehicles should be verified by the actual transfer-case type before ordering Modified, swapped, and dual-case vehicles must be verified by actual spline count and transfer-case configuration Transfer-case disassembly and gear installation require appropriate drivetrain service experience Product Specifications Brand: Sumo Gear Product Type: Transfer Case Low-Range Gear Set Transfer Case: Toyota RF1A Gear-Driven High-Range Ratio: 1.00:1 Low-Range Ratio: 4.703:1 Spline Options: 21 Spline / 23 Spline Gear Material: SCM420H Alloy Steel Manufacturing: Japan Drivetrain: 4WD Available Configurations 21-Spline For matching 21-spline RF1A transfer-case configurations Factory-style configuration for most naturally aspirated 4-cylinder manual applications 23-Spline For matching 23-spline RF1A transfer-case configurations Factory configuration for 1986–1987 22R-TE Turbo / R151F 5-speed applications Also used in properly configured upgraded and dual-case systems