Mk3 Focus ST Quaife ATB Differential - Fully Fitted at mountune HQ


Available exclusively from mountune, the Quaife ATB helical LSD differential for mk3 Focus ST fits the MMT6 gearbox. A direct replacement for the standard Ford open differential, the Quaife differential transforms your car's performance.

Unlike a conventional plate-style limited slip differential, the Quaife differential relies on gears rather than clutch plates for its operation. That means it is much smoother in operation and never locks harshly with a set pre-load of wheel slip across the driven axle.

Instead, the Quaife differential automatically biases the torque away from the spinning wheel, across the axle to a constantly varying degree.

Benefits over a standard open differential:

  • maximise traction
  • minimise wheel spin
  • reduced torque steer and snatching in front wheel drive cars
  • a maintenance-free design which retains the standard oil lubrication

Quaife differentials are proven in circuit and drag racing, rallying and road use. All Quaife differentials are produced from Corus steel billets, and are CAD-designed and CNC machined before being inspected to ISO 9001 standards.

Fitted price includes the following:

  • Focus ST Quaife ATB differential
  • Installation kit (new bearings, seals and bolts)
  • Transmission fluid

Please note: the price shown for this product includes installation at mountune HQ in Hutton, Essex and is not transferrable to any other Ford dealer or installer. 

Please specify your preferred installation date in the 'notes' section when checking-out; our workshop team will then contact you back to confirm this date. If we can't accommodate your preferred choice, the team will discuss with you other available dates, that are still acceptable to you.

Customer Reviews

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Quaife Limited Slip Differential MK 3.5 Focus ST

This upgrade transforms the car and with 280bhp+ FWD it is highly recommended. The noticeable difference to me is that the torque steer under hard acceleration is dramatically reduced which is great because you can be more secure holding the wheel one handed whilst your other hand shifts gears. Second noticeable difference is it is much harder to wheel spin off the line, particularly pulling out of junctions in first gear where as previously if you put your foot down to hard I would get wheel spin and wheel hop. That has been eliminated with this upgrade. Third difference is you can confidently put the power down earlier coming out of roundabouts and also go around bends without having to lift off because it feels as the car is on rails. I had this fitted at Mountune HQ. With regards to the customer service at Mountune on the day, it has to be one of the best experiences I've ever had in the automotive industry and probably in general too. I was greeted as soon as I got out my car by Ryan who knew exactly who I was and what I was there for and he ran through everything clearly with me. I was well looked after during the 8-9 hour day I was there (has other work done as well), their waiting room has plenty to keep you occupied throughout the day. I would highly recommend having your Mountune upgrades fitted at their HQ if, like me, you aren't mechanically able and/or want to be assured of a professional service.


Quaife Diff

Excellent product. I can't comment on wheel hop reduction as I've previously had the roll restrictor fitted and it completely killed the wheel hop (I would recommend getting that fitted too). The overall drive of the car is much better. Torque steer is now reduced and managed. It's not going to go in a 250+ BPH front wheel drive car (mine is currently running the MR275) but now it's consistent, controlled and fun, not the sudden sharp pull to the right that the Focus ST has. The steering now feels different and heavier. I had read other people say this and some didn't like it as much. I personally prefer it as it always felt too light for me, almost like steering on air, now it feels like a car. I would definitely recommend the product and would not want to drive the car without it.


Quaife Differential

Had Quaife Diff fitted at Mountune HQ. Ryan made us feel very welcome and explained everything before being made comfortable in waiting area with TV, snacks and drinks. The diff has completely transformed the car, it is now more planted to the road and able to put the power down now without wheel hoping or torque steering when pulling away. Great product, top class service from Mountune Team, everyone made us feel special. Thanks again to Ryan and workshop guys who fitted diff, it made the 300 miles round trip worth it.

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