Clutch/Trans Noise

[FredB66]

I would appreciate some help diagnosing a clutch noise. It's an 07 GT with a new T56 Magnum XL trans. When I say new I mean NEW, looks like it was installed yesterday kind of new. I've only had the car for a few months so I don't know the history and whether the clutch is new as well. I can't imagine going through the trouble/expense of a new trans without a new clutch but you never know. Anyway, while in neutral with the pedal up there's a slight grumbling sound like marbles rolling around. Push the pedal down and the sound goes away. Also, sometimes when going slow in 1st or 2nd with light load the sounds gets quite a bit louder and is more like a rattle. It goes away as soon as I hit the gas. I'm not sure if engine/road noise it masking the sound at other times. The pedal feels great and it shifts smooth so it's just the sound that's bothering me. Thoughts?

Sent from my Pixel 2 using Tapatalk

 

[rocky61201]

In neutral with the pedal up and idle at 800rpm your transmission is spinning at 800rpm as well. Push the pedal in and engine idle is still 800rpm but the transmission will slowly spin to a stop. That's why the noise goes away. Bottom line is could be a number of different things making the noise. Throw out bearing, clutch, or even something inside the transmission. If it drives and shifts fine then keep driving it. If it gets worse then revisit the issue and take a closer look at everything. T56 owners usually complain of transmission rattle sounds at low RPM anyway.

 

[01yellerCobra]

I know the T-56 is a noisy trans. Sitting at a stop light in neutral it makes all kinds of grumbling sounds. I imagine the Magnum is the same way. I wouldn't worry about it.

 

[Juice]

Mine had that noise in neutral/idle since the day I installed it. Sounds just like the T5 I pulled out along with the v6 engine. So, I'm going with it's normal. Oh, and you have to swap to a 26 spline clutch disc for the magnum xl. With the cost of the swap, you would have to be crazy trying to save a few bucks by only replacing the friction disk and nothing else.

 

[1950StangJump$]

Normal. I have the same trans, and you def can hear the light marbles sound in neutral with clutch pedal up. You can mitigate it with sound dampening materials around the gear shifter, if you want.

As for the 1st/2nd stuff, listen again. If it is between 1600 and 1900ish RPM, and the worst in 4th, you are likely hearing the sound of a twin disk clutch -- a common clutch with this trans and when adding power. You will barely hear it under low RPM load in 1st/2nd, and it will be worse in 3rd. As stated, worst in 4th. Sounds like marbles in a coffee can.

If so, that sound should also be considered "normal." It's the harmonics of the twin disk. Not all do it, but it is kind of like exhaust drone; adding different performance pieces have different side effects. Unless you're willing to spend thousands of dollars trying different combinations of parts, you'll always have these unintended consequences. Stock cars don't do it because the manufacturer spends big bucks to find the combinations that will not make the buyers twitch.

 

[FredB66]

Thanks for all the great info. I'm still in discovery mode trying to figure out what 'normal' is. I'm very happy with clutch and trans performance so I'll stick with what I've got.

Sent from my Pixel 2 using Tapatalk