Loud Rattling

Odyssey25013 · 10-17-2009, 11:40 AM

Hey guys,

Im a little new here so i dont know if this is the right place to post this but here i go

When i start up the truck in the morning, there is a loud rattling that i have narrowed down to the passanger side of the engine. It is louder underneath the truck. This happens when it is cold and the rpms are about 650-700. once it goes down a little it stops. Now it has started even when the engine is warm. If i put the rpms between 650-700 it rattles no matter what and now it rattles between 1200-1350. If it is under load it wont happen but if i let off the pedal it will rattle when going through those two rpm ranges. it is loud enough to hear in the cab with the radio on. Anyone have any suggestions on what it might be?

K9Duramax · 10-17-2009, 11:45 AM

Could just be the injector pump- is it kind of a ticking/rattling? If so, pretty typical. Any tuners on it? How long have you had it, has it done it since new? Worse case scenario start paying attention when in parking lots of places, there is always a Dmax somewhere and see if you can here it next to one in the lot to see if it may be "normal".

Odyssey25013 · 10-17-2009, 12:07 PM

No tuners and ive been able to determine it isnt the injector pump. It is a very louder rattling. it sounds nothing like any other duramax ive heard. I can hear it in the house which is 30 feet away. Ive had it for almost a year now, its getting close to 200,000 miles, but it has just started in the past few days.

twinturbo3150 · 10-17-2009, 12:16 PM

maybe your exhaust hitting against the frame of truck

Odyssey25013 · 10-17-2009, 12:21 PM

that would give me an excuse to put in a brand new big shiny one

K9Duramax · 10-17-2009, 12:22 PM

K, then yeah, start with ^^^^^^^^, maybe the shields hitting somewhere as well...

Odyssey25013 · 10-17-2009, 12:27 PM

thanks for the suggestions guys. ill check that out and get back

Odyssey25013 · 10-17-2009, 01:06 PM

i had my dad lean on the pedal and put it up to the 1300 rpm range where it is the loudest. Checked all the bolts and everything on the heat shield. They are all solid and i checked the exhast where it is near the frame and came up with nothing.

twinturbo3150 · 10-17-2009, 01:10 PM

did you contiue to hear the rattle and trace to the source since your dad was on the pedal/

Odyssey25013 · 10-17-2009, 01:29 PM

yeah. granted i couldnt pin point it. it really is that loud. it seems to be coming from the tranny. i had the transfer case replaced a couple months ago so i have a warranty on that, but its coming from the tranny specifically. i also took it out for a quick ride and around 45-50 there is a small bit of surging. the rpms stay the same and the truck seems to jump back and forth a little bit.