My T56 knocks lightly and sounds like it has loose marbles in it. It drives fine and makes no abnormal sounds when the car is moving. Fluid level is good.

What is going on?

 

let me guess, in neutral with the clutch engaged? mine has always done the same thing and i wondered why also

 

yup

 

That's the reason I bought an auto. I never liked the feel or sound of the 6 speed. I half regret it. But I still like my car to feel like it's 100%.

 

Something's wrong if the 6 speeds you've driven didn't feel 100%.. the ones I've driven certainly did.

 

Throwout bearing is what makes that noise. Its the nature of the beast.

 

Mine has done this for years and tens of thousands of miles.

Would this be the case if the noise remains when the clutch pedal is fully pressed to the floor?

 

That marble noise goes away when I press my clutch pedal to the floor.

I don't know what else would be making that noise, the tranny should be quiet if the pedal is to the floor since nothing in the trans should be turning

 

Mine does the exact same thing. i have always wondered if it was the throwout bearing?

 

Bulletin No.: 03-07-29-004C

Neutral Rattle

There are often concerns of rattle while idling in neutral with the clutch engaged. This is related to the changes in angular acceleration described earlier. This is a light rattle, and once again, vehicles with dual mass flywheels will have reduced noise. If the engine is shut off while idling in neutral with the clutch engaged, the sudden stop of the engine will create a rapid change in angular acceleration that even dual mass flywheels can not compensate. Because of the mass of all the components, this will create a noise. This type of noise should not be heard if the clutch is released (pedal pushed to the floor).


I've also heard that the throwout bearing will cause similar noises (without causing any other complaints)...

 

I'm talking about 4 brand new LS1s and multiple Lt1s. It's the tranny, not a problem with the tranny. I just didn't like it.

 

Yeah its pretty annoying, you can also hear it when your taking off right when you fully let the clutch out and start to pull away. Makes a Growl noise. Its normal, I'm on my third t/o and they all do it.

 

So again back to the question, what in the tranny causes this?

 

Well, the countershaft is ALWAYS spinning, the input shaft and output shaft are directly inline with each other, although separated merely by a bearing (pretty much) and figure you have 6 gears plus reverse (and the reverse intermediate gear) all turning ALL the time (so long as the clutch is engaged - foot off pedal) so I think it's just a lot of moving parts?? Also, the countershaft is in 2 pieces - the 1-4 cluster is one block, and the 5/6/reverse fits into the tail of that on a spline - and some of those parts aren't "tight" together.

That's my $.02 "guess", after having seen mine apart!

 

I got my rebuilt by t56rebuilds and it still does it. But if it does it under load (like maby in 4th at 20mph and give it some gas, you may needa rebuild)

I;m pretty sure the t/o bearing design /clutch fork pull try style is all to blame.