McLeod Racing RST HD Twin w/ Steel Flywheel - 11-17 Ford Mustang GT/Boss 302 5.0L - 164T

The 5.0L Coyote in a 2011-2017 Mustang GT or Boss 302 makes enough power stock to wear out the factory clutch, and add a supercharger and it will slip in a hurry. The McLeod 6435825MD is the RST HD twin disc with a steel flywheel built for these cars and their factory six-speed: 1 x 23 spline discs and a 164 tooth ring gear. If you are searching for a fix for MT82 clutch slip, chatter, this is the bolt-in twin for it.

What this twin disc does behind the Coyote

Ford's clutch is a single disc. The RST HD replaces it with two discs and an intermediate floater plate, giving the pressure plate four friction faces to clamp. More surface area means more torque capacity at a reasonable pedal effort, and McLeod says this one is lighter than stock. One face of each disc is full organic for gentle engagement, the other is segmented ceramic for bite once the car is making boost. McLeod rates it at up to 950 horsepower, which covers most blown and turbo Coyote street builds.

The included steel flywheel replaces the factory flywheel. Steel keeps enough inertia for easy launches and stop-and-go driving. Expect the kit to ship at around 45.2 lb.

Symptoms on a 2011-2017 GT

• Rpm flare in third or fourth at full throttle, especially after a tune or power adder
• Chatter or shudder when pulling away from a stop
• Burning smell after launches, autocross or road course sessions
• A clutch that grabs high in the pedal travel as the disc wears

Confirm the diagnosis first

Hard-to-select gears on an MT82 are not always the clutch, so start with a slip test: fourth gear near 2,000 rpm, full throttle, watch the tach against the speedometer. A tach that climbs ahead of road speed means slip. Then check the hydraulic side, including fluid level and a bleed, because the 2011-2015 cars use a concentric slave that can leak inside the bellhousing. Our guide to diagnosing slipping covers the rest, and the repair cost guide lays out typical labor.

Fitment

McLeod lists this kit for 2011-2017 Ford Mustang GT and Boss 302 5.0L, with a 1 x 23 spline and 164 tooth ring gear. The 2011-up GT uses the Getrag/Ford MT82 six-speed, and the Boss 302 returned for the 2012 and 2013 model years with the same 5.0L family. The 2015-2017 cars are the newer S550 body; the listing covers them, but bellhousing and hydraulics differ between generations, so send your year and VIN if you want us to double check. If your car has been swapped to a gearbox with a 1-1/8 x 26 input, you need the 26 spline RST HD for 2005-2017 Mustangs instead. For a single-disc option, see the McLeod Super Street Pro for 2015-2017. Browse more in our hard parts section.

Install notes

• Replace the concentric slave cylinder while the gearbox is out; for 2011-2015 cars the Exedy slave cylinder and release bearing fits. Confirm bearing height for the twin before final assembly.
• Install a new pilot bearing in the crank.
• Clean the MT82 input splines and check that each disc slides freely before stacking the assembly.
• Follow McLeod's disc orientation markings and line up the alignment marks on the pressure plate and floater.
• Tighten the pressure plate nuts to 25 ft-lb, then 35 ft-lb, alternating across. Do not use thread locker. Use the supplied adapter ring bolts without washers.
• Bleed the clutch with fresh fluid of the type your owner's manual specifies, then give it about 1,200 easy engagements of break-in.

Does this bolt in with the stock MT82 transmission?

Yes, that is what the 1 x 23 spline is for. McLeod lists it for the 2011-2017 Mustang GT and Boss 302 5.0L.

Will it fit a 2015-2017 S550 GT?

The listing covers 2015-2017, but those cars have a different body and hydraulic setup from the 2011-2014 cars. Send us your VIN and we will confirm before you order.

Should I replace the slave cylinder too?

Yes. The concentric slave lives inside the bellhousing, so replacing it now avoids pulling the gearbox again. Set the release bearing height for the twin disc.

How much power will it hold?

McLeod rates the RST HD twin at up to 950 horsepower, with a lighter than stock pedal.

What is the difference between this and 6435807MD?

Spline. This kit is 1 x 23 for the factory MT82. The 6435807MD is 1-1/8 x 26 for Mustangs swapped to a gearbox with that input.

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