McLeod RST Twin Disc Clutch Kit 18-19 Ford Mustang GT 1 x 23 Spline 0 Bal w/164T 8 Bolt AL...

If your 2018 or 2019 Mustang GT now makes far more power than the factory clutch was built for, the first signs are usually slipping in third and fourth at full throttle, a burnt smell after a hard pull, or a pedal that has started to feel inconsistent. McLeod part number 6333825 is the RST twin disc clutch on a dedicated billet aluminum flywheel for the Gen 3 Coyote 5.0L and the factory MT82 six-speed, splined 1 in. x 23 to bolt in behind the stock gearbox.

What the RST twin clutch does in a 2018-19 Mustang GT

A twin disc clutch splits the job of holding torque between two friction discs with a floater plate between them. With twice the friction surface, McLeod can hold much more torque without a heavy pressure plate, which is why the RST pedal is rated lighter than stock. The RST is the organic version of the design: McLeod rates it to about 800 horsepower and describes it as a street clutch with smooth engagement, not a competition part. That makes it the right pick for a supercharged or bolt-on GT that is driven daily and launched occasionally, rather than a drag car.

In this part number the clutch comes already assembled to an 8-bolt billet aluminum flywheel with a 164 tooth ring gear and zero balance, so you buy one box instead of matching a clutch and a flywheel separately. It replaces the factory dual mass flywheel, which removes a lot of rotating weight. Expect quicker revs and a bit more gear rattle at idle than stock.

Symptoms that point to a clutch upgrade

• Clutch slipping under load: rpm climbs without the car pulling harder, most noticeable in higher gears.
• Smell of burnt friction material after a launch or a track session.
• Pedal engagement point moving or the pedal feeling soft and uneven.
• Chatter or shudder on takeoff from a glazed or oil-soaked disc.
• Grinding or hard engagement into gears when the clutch does not fully release.

How to confirm the clutch is the problem

Rule out the hydraulics before buying. A leaking or air-filled slave cylinder causes poor release and grinding that can look like a worn clutch; a bleed and a look at the fluid level often fixes that. True slip shows up as rpm rising with no matching gain in speed, usually in fourth gear from low rpm with the throttle pinned. Our slipping diagnosis guide walks through telling a slipping clutch from other driveline problems, and the clutch chatter guide covers shudder on takeoff.

Fitment

This listing is for the 2018-2019 Mustang GT 5.0L with the 6-speed manual. McLeod's own application line for 6333825 reads 2018-22 Mustang 5.0L, 8-bolt crank, 1 x 23 spline, 164 tooth, 0 balance, so later S550 GT cars with the factory gearbox use the same spec. McLeod lists 2015-2017 GT cars under other part numbers, so match your model year. It is also not for a car that has been swapped to a 1-1/8 in. x 26 spline gearbox. For that, see the 26-spline version, 6333807. If you are not sure what is behind your engine, send us your year and VIN before ordering.

Need more holding power? The RXT ceramic version, 6333825M uses the same flywheel spec for higher power builds.

Install notes

• The pressure plate nuts go on with flat washers, then lock washers, then nuts, finger tight. Torque to 25 ft-lb in a star pattern, then to 35 ft-lb in the same pattern. No thread locker on the studs.
• Install the disc marked bottom against the flywheel, facing the flywheel side mark, and line up the drive straps and alignment marks on the floater and pressure plate.
• Slide both discs on the input shaft by hand first. They must move freely on the spline.
• Check the pilot bearing and replace it if it is rough. A pilot bushing remover makes this easier, and a clutch alignment tool kit is a good backup to the supplied tool.
• Bleed the hydraulics with fresh brake fluid of the type on your reservoir cap.
• Break it in with about 1,200 normal shifts on the street, traction control off. McLeod says not to break it in on a chassis dyno.

Still comparing single and twin disc options? Our clutch kit buyer's guide lays out the trade-offs.

Will McLeod 6333825 fit my 2018 Mustang GT with the stock six-speed?

Yes. It is built for the 2018-up 5.0L with the 8-bolt crank and the factory 1 x 23 spline input, with a 164 tooth ring gear and zero balance. For a 2015-2017 GT, check McLeod's application for your year first.

What is the difference between the RST and the RXT?

The RST uses organic discs and is rated to about 800 hp for street driving with smooth engagement. The RXT uses ceramic discs for higher power and harder use, with more aggressive engagement.

Do I need a new flywheel with this kit?

No. This part number includes a dedicated billet aluminum flywheel that replaces the factory dual mass unit. Do not add or remove weight from the adapter ring if the assembly is balanced.

What should I replace at the same time?

Check the pilot bearing, the release bearing and the slave cylinder while the transmission is out, and fix any rear main or input seal leak first. Oil on the discs will ruin a new clutch.

How do I break in the clutch?

Drive it normally for about 1,200 clutch engagements with traction control off before launching or racing. McLeod advises against breaking it in on a chassis dyno.

• Transmission Slipping Diagnosis Guide
• Automatic vs Manual Transmission Repair Cost
• Shift Flare vs Slip: How to Tell the Difference