Truck- 2007 5.9 87,000 miles, 6 sp manual.
New clutch (DMF, TR, PP, Disc) installed by a dodge dealer.
Dealer found the crank walking. Turns out the thrust bearing was broken. The journal was worn so I elected to buy a short block from Cummins. Long story short, the dealer did not win the business to change the motor.

Install went well- engine runs fine, but the clutch (DMF?) rattles when in idle... It wasn't rattling before the short block change. We even swapped out the old DMF for the new and had the same rattle.

Also, the truck shakes more at idle than I remember. We put a computer on it and turned off each injector to see if there was a bad one... but they all seem fine.

What could be causing:
1) the rattle in the clutch?
2) the shake at idle?

Could they be connected? Can a rough idle cause the DMF to rattle?

The truck runs great on the road... really well, actually...

We reused the harmonic balancer... it is the factory stock unit. Could that be the issue? Do they go bad? Or wear to a particular engine? Is there some idle adjustment I have to make?

We're stumped.

TIA

 

I'd start by getting rid of the dual mass flywheel setup! They are notorius for causing problems. My neighbor across the street fought it for 2 months trying to figure out why the truck was shaking. Finally after taking my advice he ditched the DMF which only had 40k miles on it for a single mass and everything was smooth afterwards.

Other than that I'm not sure what to look for next.

 

Well- the thing is the DMF is brand new. As is all the rest of the clutch... I tried a phoenix friction SMF first, and it didn't fit right, and their customer support is trash. I won't do business with them again. After that, I put in a factory clutch set up because I didn't want to be burned *again*. The factory set-up was working fine until the short block change.