Chattering when shutting down?

Are you fairly certain that the noise is coming from the tranny? Could it be something that is loose rattling under the cab/hood?

 

Next time you shut it down "lightly" keep you hand on the shift lever, see if it still rattles. Also I would suggest next time you have the truck on a pit for a service ask the tech if he would mind looking for anything loose underneath, or better still if he would stay under the truck during shutdown to see if he can determine anything from underneath. Just what I would do.


BTW, what year, make, model,engine do you have?


Stan

 

Maxxforce 10 is the old DT 408/466/530 architecture. Other than something loose under the truck all I can think of off the top of my head would be clutch fork or linkage hitting floorboard, unless it is HYD. Possibly could be a throwout bearing, have you had it back to the dealer?

 

I have one that does the same thing, I think. Shut it off, a little clunk, then a rattle. Been doing it for 6 years, never been a problem. N-14 Cummins with Eaton 10 speed.

 

Have you tried holding the clutch all the way in and engage the clutch brake, then shut it off, if nothing changes I would think you could eliminate the throwout bearing.

 

The noise you are hearing is perfecting normal, infact, if you don't hear it something is wrong with your engine! The noise is coming from the exhaust back pressure valve located right after the turbo. This is a butterfly valve controlled by a pneumatic cylinder. The engine will cycle this three times at shut down to loosen any built up carbon.

 

That's why I kept asking if he was SURE it was from the tranny. I know also that sometimes I shut down one of our Ultrashifts and have someone walk by and wonder what the noise is while the tranny is cycling. Too bad they can't cycle the EGR valve. lol