McLeod twin disk knocking
 

Looking for some other people input...…

Installed a McLeod twin disk on my Gen III Hemi, T56 Magnum build and its noisy as hell. New trans, new pilot, did the bell alignment, new McLeod flywheel, had a local shop balance the assembly etc etc.... so as far as I can tell I did the install spot on...

When the trans is in neutral and clutch out, it knocks like crazy.... best comparison I can make is it sounds like rod knock..... push the clutch in.....totally quiet.

Talked to the guys at Bowler... the company I purchased it through....sent them a video and their feedback is that they have had several McLeod twin sound just like that.... customer brought cars back, thinking something was wrong too..... so apparently this is "normal" for these set up..... WTH... they basically feel like the are noisy but work just fine

Some other stuff came up and I had to pull the motor and trans anyway, so its all out of the car now and visually it looks normal. The car was only run around the block a few times, so the set up has less than 3-5 miles tops.

I'm going to call McLeod and get there input but looking for some real world unbiased opinions.... thoughts?

I have had similar issues with Centerforce Dyads......I have had some of those that were quiet.

***Edit, I missed that the noise goes away when you push the clutch in......which is the opposite of what happens when the floater discs start rattling around.

Spec super twin is noisy when the clutch is pressed. Put in neutral and let clutch out and it quiets down. That to me is normal for multi-disc clutch setup.

For it to be noisy with the clutch OUT in neutral seems weird to me. Discs should be locked and turning with the Pressure Plate / Flywheel.

If the throwout is fork style then it could be the lever getting jammed inside bellhousing because the clutch pack is thicker (and the flywheel could be a tick thicker) and the fork is pushed back steeper angle.

If it's hydraulic TOB then it could be the TOB housing or NEW trans casting hitting the pressure plate or pp retaining bolts when the crank moves rearward a few thousandths in it's thrust bearing when pedal pressure comes off.

Could be a complication inside the pp if you've over stroked the fingers.....lets hope not.

As will69 said "it should be noisy disengaged" (pedal down) cos the intermediate plate between the friction plates will rattle in its retaining bosses. That will be a rattle NOT rod-knock-sound.
Later....

By far the most quiet twin disc I've run so far is the RAM. I'm running a hybrid version from them on my Magnum now that's good for up to 700ft/lbs or more. Acts and sounds just like an OEM clutch. I couldn't be happier with it.

I have a McLeod RXT behind my T56 Magnum and it's pretty quiet at idle in neutral. I do get gear rattle from the transmission at around 1800-1900 RPM in gear but my clutch isn't noisy.

Still dealing with this issue...

The rattle is in neutral, clutch out, car at idle......... push the clutch in and noise stops about 1/2 way in..... so it sounds like opposite of what other people are saying when they have some rattle from a Twin disc set up

I can rev the motor pretty high and don't hear or feel a vibration....

I had local machine shop balance the flywheel and clutch.....could they have F-ed it up?

I’ve had the same issue. Trans and Clutch coming out shortly. I’ll let you know what I find.

Hey Curtis
Due to a motor issue I had to pull everything out and it all looked visually normal. so I couldn't find a source....put it all back together after verifying bell alignment and being very careful to make sure everything was installed correctly.... still there

There is another thread in the main general forum where it was mentioned that the noise may be from the T56, not the clutch assembly.... doesn't sound like gear whine... more like a knock to me

Your description is spot on to what I've been experiencing. Just blew the rear seal out of my T56 while racing a AMG GT-R on the freeway (I won, so totally worth it) and may upgrade to the Magnum-F (F-Body) if it will fit. I'll let you know if it goes away.

I'm starting to lean towards it actually being the T56 and not the clutch.....

Got under the car again and tried to listen real close....even used my stethoscope...... it still hard to know for sure but I can hear it just as well on the trans as the bell.. maybe even a little louder.... the case is thicker and listening through oil, so its hard to really be sure

Plus I have noticed that it seem louder as the car warms up.... like if the oil was warming up ...... plus makes more sense if the noise is gone when the clutch is IN........ and you can rev the motor up high and no noise at all....

For clutches with non-sprung hubs like the Mcleod, sitting in neutral with the clutch engaged (foot off the pedal) can often generate gear rattle in the transmission that is then carried up through the shift handle. The non-sprung clutch hubs don’t absorb any vibration from the engine firing events and the gears “knock” back and forth against each other. A bigger cam with a lopey idle exacerbates this issue. Gear rattle is a big reason why OEMs like to use dual mass flywheels, they smooth out the torque delivery to the transmission especially at lower RPM and cut down on NVH. (Of course, a dual mass flywheel presents another can of worms if/when the moving elements inside it decide not to move anymore or the springs break.)

The transmission gear rattle with a solid hub clutch may also be audible while driving at lower RPMs as the solid hubs won’t dampen the pulsations from the engine. Accelerating in overdrive gears at lower RPM tend to be the worst for this as the torque requirements are higher and engine RPM is lower.

If it’s gear rattle, you can always try isolating the shift handle like the OEMs do, often with a rubber isolator in the handle itself. That will help cut down on the amount of gear rattle carried into the car. A buddy has a 2006 GTO with a Monster dual disc clutch with solid hubs. The gear rattle was barely detectable with the stock shifter and handle which had some rubber isolators, but when we put in a Ripshift shifter, a bronze shift bushing, and a solid mounted steel hurst shift handle the gear rattle at idle and at low RPM in 5th and 6th became much more noticeable.

With a dual disc clutch like the Mcleod, any noise with the clutch depressed while sitting stopped is usually the floater plate in the clutch moving around a bit.

Interesting.. thx for the info..

You cant really hear or feel the noise from inside the car but outside with it idling.... and kneel down or get under the car and you can definitely hear the "rattle".....if you stick your head in the engine bay back by the bell you can hear it... but otherwise its not real obvious unless you know its there... which I do, so I'm hyper aware of it....

Since the noise isnt really transmitting into the car via the shifter, I dont think an isolator will help in this case

Think I'm going to just run it..... I at least feel more comfortable knowing that I'm not crazy and its nothing that its truly "wrong" where something bad is going to happen if I dont ID and fix it

If your bellhousing alignment was good, and nothing in the clutch or throwout bearing are rubbing inside the bellhousing, I'm pretty sure you're dealing with gear rattle, especially since you said you really only hear it stopped in neutral with the clutch out.

What fluid are you running?

Thinner fluids like ATF make the rattle a little worse since it's such low viscosity.

The rattle gets quieter with syncromesh since it's a little thicker and dampens the gear contact better (Tremec brands their own blend of syncromesh fluid now, HP-MTF)

It's even quieter still with Redline Superlight shockproof.

Years ago Dodge had a TSB for gear rattle in the T56 in the Vipers... the "fix" was thicker fluid.

Worst neutral clutch out gear rattle I've ever heard was in a brand new C6 Z06... sounded like a paint can half full of rice being aggressively shaken behind you. LOL!

I'm just running the Dexron III that the big orange sticker on the site of the trans says to use.....
As I noted before, the noise seems to get more noticeable once the car has warmed up, so I was wondering if it had to do with the oil getting warmed up and thinner....

No harm in swapping out the fluid and see what it does....

This the one you are talking about?
https://www.summitracing.com/parts/red-58404

Or maybe this?
https://www.summitracing.com/parts/rpo-01512

Ned,

The fluid Tremec had made to their specs is this:

https://www.summitracing.com/parts/awr-tukt-16993

Not sure who's making it for them. Pennsoil, Valvoline, AMSoil, and Royal Purple all seem to make variants of syncromesh fluid.

While I haven't tried it yet, it's probably hard to go wrong with the fluid that the manufacturer says will have the best results.

As far as the Redline shockproof, I've tried the lightweight and superlight shockproof in the T56/TR6060. The lightweight shockproof is thicker and will better dampen gear rattle, but IMO it's too thick and makes the already notchy T56/TR6060 shifting (especially into 2nd gear when cold) even notchier. The superlight shockproof is better suited IMO.

Holy smokes 91 dollars for 4 quarts of tranny fluid is crazy. You can get the AMSOIL product for 10 dollars less a quart and you know who makes it.
Ned they have free shipping on orders of 49 dollars. Use Promo code SHOP1220
Heres a link to the product: Synchromesh

Even better news.... the trans rear seal was leaking...come to find out I have one of the Tremec tail shafts that they forgot to machine the small drain holes into... so I have to remove the tail shaft housing and swap it out with a new one that Tremec is replacing under warranty...... but I have to pull the trans to remove it..... joy....

Welcome to the club brother! :captain: