Drivetrain› Differentials and Rear-End Components

Mountune

Quaife ATB Limited Slip Differential

$1,199.00

SKU: 2363-ATB-AA

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Mountune Quaife ATB differential is a helical limited-slip differential designed for the Focus ST and MMT6 gearbox. It serves as a direct replacement for the standard Ford open differential, aiming to enhance vehicle performance and improve cornering capabilities. Unlike traditional plate-style limited-slip differentials, this unit utilizes gears for operation, resulting in smoother engagement and continuously varying torque bias to the wheel with the most grip.
Show original supplier description
The Mountune Quaife ATB Differential is a direct replacement for the standard Ford open differential in the Focus ST equipped with the MMT6 gearbox. Its gear-driven design operates smoothly, automatically biasing torque to the wheel with more grip, thereby minimizing wheel spin and reducing torque steer common in front-wheel-drive vehicles. Constructed from durable Corus steel billets, this differential is meticulously CAD-designed and CNC machined to meet stringent ISO 9001 quality standards. It offers a maintenance-free operation, utilizing the vehicle's standard oil lubrication system. The Quaife ATB differential has a proven track record in circuit and drag racing, rallying, and everyday road use, ensuring reliability and enhanced driving dynamics. This unit is specifically designed for the 2013-2018 Ford Focus ST models with the MMT6 gearbox. It is important to note that this part is intended for off-highway application only. Installation on a vehicle driven on public roads may violate emission requirements and motor vehicle safety standards in the U.S. and Canada. Additionally, buyers should be aware of California's Proposition 65 warning regarding potential exposure to chemicals known to cause cancer and birth defects.
Vehicle Symptoms
  • Excessive wheel spin on launch in first gear
  • Torque steer pulling wheel under hard acceleration
  • Inside wheel spinning during hard cornering
  • One-wheel peel from a stop sign or traffic light
  • Difficulty putting power down on wet or loose surfaces
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Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandMountune
Part Number2363-ATB-AA
CategoryDrivetrain
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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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