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 ATB upgrade also 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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Excellent upgrade

Well worth the 260 mile round trip. The car is much firmer on corners and torque steer greatly reduced, thanks to the friendly and efficient team at Mountune.


Quaiff diff

Excellent performance and experience. Ryan was vey helpful and explained to me which items on my car need attention. Fred appreciated for sort my stuff out. these guys are proper Ford performance specialist quaife diff fitted and carried out other work on car all within 1 day waiting while I was chilling out at waiting room very good experience. A lot of tuning places won't able to carry out this task within the day they would need to remove gearbox and send it away for specialist to fit the diff these Mountune guys are awesome. Looking forward to deal with these guys again in future when they make a hybrid turbo for the mk3 st Focus


Quaife Diff

Had diff fitted at hq. Could not say anymore the service is the best can chill at waiting room while work is carried out and Ryan Sinclair is very friendly and helpful give me all advise on my car. Also Fred thanks for sort things out for me appreciated. I have to say these Mountune team are the proper Ford performance specialist can fit me a diff and carry out other work within a day not many tuners can do that normally take 2 days or a week for them to send gear box away and let specialist to fit it. Highly recommended. Hopefully you guys can look into a hybrid turbo with a stage 3 map for the Focus st mk3

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