McLeod Racing RST HD Twin w/ Aluminum Flywheel - 2018-2023 Ford Mustang 5.0L 8 Bolt Crank -...

The McLeod 6333825MD is for the 2018 to 2023 Mustang GT owner whose 5.0L Coyote now makes more power than the factory MT82 clutch can hold, but who still drives the car on the street most days. It is McLeod's RST HD twin disc on a dedicated billet aluminum flywheel, built for the stock 1 x 23 metric spline input, the 8-bolt crank and the 164 tooth ring gear.

What the RST HD twin does in a 2018-2023 Mustang GT

McLeod places the RST HD between its two long-running twin disc lines. The plain RST uses organic discs for the softest engagement, and the RXT uses ceramic for maximum bite. The RST HD splits the difference inside each disc: one face is full-face organic material for smooth, quiet take-off, and the other face is segmented ceramic for extra grip once the load climbs. McLeod rates it for up to 950 horsepower and describes the pedal as lighter than stock.

On an S550 that means the clutch can take a supercharged or turbo Coyote without the chatter and grab that an all-ceramic twin brings in traffic. The aluminum flywheel replaces the factory dual mass unit, so the engine revs more freely and the drivetrain loses a good chunk of rotating weight. Expect a little more care pulling away from a stop and some gear rattle at idle, which is normal once dual mass damping is gone.

Signs your Coyote has outgrown the stock clutch

• Rpm flares on a full-throttle shift after a tune, supercharger or turbo kit
• Slip in fourth through sixth when you roll into the throttle from low rpm
• A clutch that holds when cold but starts slipping after a few hard pulls
• Burning smell after a launch or a stop on a hill
• Shudder or a knocking rattle from a worn dual mass flywheel

How to confirm it is the clutch

Do a high-gear slip test: in fifth at around 2,000 rpm, go to full throttle and watch whether engine speed rises faster than road speed. Before you blame the disc, check the hydraulic side. A low or dirty reservoir, a weeping slave cylinder or a pedal that slowly sinks can keep the clutch from clamping and feel exactly like slip. Our transmission slipping diagnosis guide walks through separating slip from other faults, and the manual repair cost guide helps you budget the labor.

Fitment

McLeod catalogs this kit for the 2018-2023 Ford Mustang 5.0L with the 8-bolt crank, 1 x 23 metric spline and an aluminum flywheel carrying a 164 tooth ring gear. That spline matches the factory six-speed manual, so it is not for cars swapped to a transmission with a 1-1/8 x 26 input; those need the 18-23 Mustang twin with 1-1/8 x 26 spline. It does not fit the 2024-up S650. If you want more street comfort and less power, compare the organic RST twin for the 2018-up GT; for a bigger build, the all-ceramic RXT twin 6333825M uses the same flywheel layout. Not sure what is in your car? Send us the year and VIN before you order.

Install notes

• Find out why the old clutch failed. If there is oil on the old disc, fix the rear main or input seal leak first or the new discs will be contaminated.
• Replace the pilot bearing; a pilot bushing remover pulls it without damaging the crank. A release bearing is not listed as part of this kit, and McLeod recommends replacing the factory slave on twin disc installs.
• Slide each disc onto the input shaft by hand first. They must move freely on the 23 spline.
• Fit the disc marked bottom with its flywheel-side label toward the flywheel, keep the drive straps and alignment marks stacked, and center it with the supplied tool.
• Pressure plate nuts go to 25 ft-lb, then 35 ft-lb, in a star pattern with no thread locker.
• Bleed the hydraulics (our clutch bleeding walkthrough covers it), then give the clutch about 1,200 normal street engagements before hard launches. McLeod says never break it in on a chassis dyno.

Does this fit a 2018-2023 Mustang GT with the factory six-speed?

Yes. McLeod lists it for the 2018-2023 Mustang 5.0L with the 1 x 23 metric spline used by the factory MT82 manual, the 8-bolt crank and a 164 tooth ring gear. Send us your VIN if the car has a swapped transmission.

What is the difference between the RST HD and the regular RST or RXT?

The RST uses organic discs, the RXT uses ceramic. The RST HD discs carry organic friction on one side and segmented ceramic on the other, for more holding power than the RST with smoother street engagement than the RXT. McLeod rates the RST HD at up to 950 horsepower.

Do I keep my dual mass flywheel?

No. This package comes with its own billet aluminum flywheel for the 8-bolt Coyote crank, so the factory dual mass flywheel is removed.

What else should I buy with it?

Plan on a new pilot bearing, and McLeod recommends replacing the factory hydraulic slave at the same time. A release bearing is not listed in this kit. Fresh brake fluid for bleeding the clutch hydraulics is also needed.

How do I break it in?

Drive it normally for about 1,200 clutch engagements, shifting up and down through the gears with traction control off. Do not break it in on a chassis dyno, and save launches until after break-in.

• Transmission Slipping Diagnosis Guide
• Automatic vs Manual Transmission Repair Cost