Subaru OEM Subaru 4EAT Front Ring and Pinion Gear - 4.11:1 ratio | 38100AB390

Overview

The Genuine Subaru OEM 4EAT Front Ring and Pinion Gear Set (Part #38100AB390) is a factory-original replacement gear set engineered specifically for Subaru vehicles equipped with the 4EAT automatic transmission. Featuring a 4.11:1 final drive ratio, this precision-machined gear set restores factory drivetrain performance and ensures seamless power transfer from the transmission to the front differential. Designed for Subaru owners who demand exact-fit reliability and OEM-grade durability, this is the same component installed on the assembly line.

Key Features & Benefits

• Genuine Subaru OEM Part – Manufactured to factory specifications for guaranteed fit, function, and longevity — no modifications or adaptation required.
• 4.11:1 Final Drive Ratio – Maintains the factory-specified gear ratio for correct speedometer calibration, fuel efficiency, and drivetrain balance.
• Precision-Machined Gearing – Crafted from high-strength alloy steel with tight tolerances to minimize noise, vibration, and heat buildup under normal and demanding driving conditions.
• Direct-Fit Replacement – Engineered as an exact replacement for the original ring and pinion, eliminating guesswork and reducing installation time.
• Factory Warranty Eligible – As a Genuine Subaru OEM component, this part is backed by Subaru's standard OEM parts warranty when installed by an authorized dealer or qualified technician.
• 4EAT Transmission Compatibility – Specifically designed for Subaru's 4-speed automatic transmission (4EAT), ensuring proper engagement and long-term reliability.

What's Included

• 1x Genuine Subaru Front Ring and Pinion Gear Set

Specifications

Fitment & Compatibility

This Genuine Subaru ring and pinion gear set is designed for Subaru vehicles equipped with the 4EAT automatic transmission and a 4.11:1 final drive ratio. Please verify your vehicle's transmission type and existing gear ratio before ordering. Typical applications include:

Important: Always confirm fitment using your vehicle's VIN or consult a Subaru dealer parts department to verify this is the correct ratio and part number for your specific model year and trim level. Final drive ratio must match your existing transmission build.

Installation

Replacement of the front ring and pinion gear set is an advanced transmission rebuild procedure requiring specialized tools, including a press, bearing pullers, and gear-lash measurement equipment. This repair is not recommended as a DIY job for general consumers. Professional installation by a qualified Subaru technician or transmission specialist is strongly recommended. Proper gear backlash, preload, and bearing setup must be set to factory specifications to ensure noise-free operation and long service life.