growling on startup

[Mstephens]

Has anyone had a strange noise when starting. The first time it did it I thought an animal had crawled into the fan when I started up. It only does it when the truck sits for awhile(week or longer). It does it right when I start the truck and only "growls" for a few seconds. This makes it very hard to diagnose, and the garage says they cant find any problems. At first I thought it may have come from the engine compartment, but now I think maybe under the dash, or firewall area. Any help would be appreciated.

Truck is a 2007 R/C 4x4 2500

 

[DrDiesel]

When the starter solenoid sticks/hangs, it can cause the Bendix gear to stay engaged on the flywheel and grind/growl. This could be what your experiencing.

Also be advised, if the starter pivot is worn/wearing out or the return spring is broken this will also happen. :{

 

[Mstephens]

I dont think this is the problem, sounds almost like plastic, not a starter grind. And it only does it after the truck sits for extended periods, not every time I start. I was wondering if it could possibly be vacuum related?