Clutch Grinding?

[jdbecker2]

So I started my truck yesterday and when I let off the clutch, there was a grinding noise that I could feel through the pedal. When the revs were up on the truck, above 1000, it went away. It was really bad on the way to school, now it hardly makes a noise except when I shut off the truck. Just a few notes, its cold here (0*) and the Smarty has never been over three. Any help would be much appreciated.



Thanks,

Jake

 

[Regcabguy]

So I started my truck yesterday and when I let off the clutch, there was a grinding noise that I could feel through the pedal. When the revs were up on the truck, above 1000, it went away. It was really bad on the way to school, now it hardly makes a noise except when I shut off the truck. Just a few notes, its cold here (0*) and the Smarty has never been over three. Any help would be much appreciated.



Thanks,

Jake

I can't address the grinding noise,but whenever I shut mine off I make sure the clutch is in and transmission is in neutral. This minimizes the racket. Someone on here said it's the DMF making all the noise.

 

[GCroyle]

Jake,



Can you add more info please?

Noises when you release the clutch? (pedal down)

Noises when you engage the clutch? (pedal coming up)

Try it with the engine off also.

Noises during upshifts, rolling gear changes?

Noises while cruising?

Noises related to load, light load heavy load?



One test to try, select neutral, engine running, accelerate the engine,feel for vibration.

 

[jdbecker2]

When the pedal is down the noise is the loud, when its under load its even louder, only while engaging. At crusing speed there is no noticeable noise. Also, no vibration when the truck is off, but with the truck at idle its there again.



Thank you,

Jake

 

[GCroyle]

Jake,



Please restate:



"Also, no vibration when the truck is off, but with the truck at idle its there again"



Is it a metal to metal shrapnel sound or a howling? One other thing might be to carefully try to stethoscope the transmission and see what controls the noise and where does it seem to be coming from. Any shifting issues?

 

[jelag]

Hi Gary.....

We've got our 5500 on the road with the new Aisan Transmission. . It might put us out of business... . I'm impressed... .

 

[jdbecker2]

Sorry about that. When the clutch is released and engaged when the truck is off there is no sound, but when running the noise starts at low rpm and disapears at anything over 750 rpm. No shifting issues at all, and its definatly a metal on metal grinding sound.

 

[GCroyle]

Hold the phone next to it!

Jake,



1. Pilot bearing is "active" when engine is running, trans in gear and clutch is released, not transmitting torque. When the clutch is engaged, pilot is not "active".

2. Release bearing is turning continuously, it never pulls away from the diaphragm spring, the load applied to the bearing varies with pedal position, engaged = light bearing preload, 1/2 way down (approx) = high load est. 400 Lbs at the bearing, pedal at floorboard = est. 300 lbs. Dont get too hung up on the numbers, I don't have the test reports here at home.

4. Dual Mass Flywheel, this has a damper assembly in between the primary flywheel and the secondary flywheel, quite a collection of parts.

5. Clutch disc. The G56 has a torsion damper in the disc, multiple parts, springs, thrust rings, wave springs, etc.

6. Clutch cover, the G56 uses a self adjusting cover, it compensates for a decrease in disc thickness (over time, normal wear and tear) uses wedge ramps, springs, sensor spring, again quite a collection of parts.



Any of the above COULD make noise in the wrong condition/situation, now we have to listen close, and try to plug the noise into the correct component source.



Any luck with stethescoping yet?



Dealers coments?