Duramax sounds like a F$%D

[JimErickson]

Help,
Just recently (last 2 weeks) my 2001 Duramax 3500 with Allison tranny has started sounding really loud. Sounds a lot like a Ford now......

Even had to shut off truck to go through a drive-through.

Any ideas on why this would happen?

No loss or gain in power noticed.

Thanx
Jim

[RRHOGGER]

Combustion noise is a result of High peak combustion preasures. The factor that affects noise the most is timming - the more advanced the more the noise. Could also be something wrong with the way the ICM is handling the pilot injection i.e. not working. Best to get it checked out.
Hog