Clatter during shut-off

[VA_Dmax]

I have been experiencing a loud clatter when I shut my duramax off. Being my first diesel, Ive listened to several other Duramaxes thinking maybe this was normal. It appears that it is not. However I have only been able to hear allison equipped trucks shut off. Could this be the difference? Anyone with a ZF get a loud clatter when they shut it off? I had a buddy listen with the hood lifted when I shut it down and he said he thought it was coming from the accessory belt at the alternator and it was skipping on the alternator pulley. If an alternator was going bad would this cause a clatter? Is it possible for one to go out at less than 8k miles? Thanks for any help.

[DinoMax]

VA_DMAX, it is "normal" for our trucks to do that. Basically, you friend was on the right track. It is the serpentine belt causing the noise. The engine is making another revolution at shut down, but with no power to accessories/pulleys at this point, it causes the belt to slip. There were some threads on this a while back, and you can either get used to the noise, or replace your belt with a Goodyear Gatorback. That seemed to cure it for the ones that made the change. If you do a search under belt squeak, I think the part # for the belt was listed. Good Lock, DinoMax

[mackin]

The "clatter" is just the duramax coming to a halt ,along with a "Chirp" from the serpentine is do to the high compression of the Max ...Stops mighty quick when you take the fuel away ..... ;)

Mac :D :D :D

[VA_Dmax]

Thanks for the answers and info! I might look into that replacement belt, it doesnt bother me so much now knowing that it is pretty normal for that to occur.

[Wally]

Without being there to listen. I couldn't say for sure. Try shutting it down with the clutch pedal depressed. If the noise goes away or is a lot quieter then what you are hearing is the Dual Mass Flywheel rattling. If this is the only noise it makes then it really isn't a problem.
Yet!

[VA_Dmax]

Wally, I did what you said and put in the clutch and sure enough the clatter stopped, and I could then hear that belt squeek, so it was a combo of both it looks like. I guess that means its a matter of time before I lose my flywheel? Or is this something that will happen with the dual mass whether it is good or bad? Thanks!!

[MEP]

VA_Dmax,
I agree with Wally. The DMF does rattle when shutting down. It sounds like a catalytic converter heat shield rattling. I have a 2001 and my DMF failed at 24k miles. I now have 41k miles and have not had a problem since. But read on. My original DMF rattled twice as loud as my replacement. It rattled loud since the day I brought the truck home from the dealer. When my flywheel failed, the engine would shake pretty bad during idle but run smothly during driving. I drove almost a whole summer like this until the clutch started slipping pretty bad.

Jim B
DP member #739

[Wally]

Yea what MEP said.
Mine rattled from day one also and had begun to vibrate while running down the road. About three weeks after I sold it the new owner had to have it replaced. Supposedly after the 2001 model year GM improved the flywheel but I know of two people besides my Ex truck that have had to have it replaced on 02s. It is covered by the 100K warranty.