Just got done giving my 04.5 2500 it's 12,000 mi service. I have been going on a 6000 mi service rather than 7500 mi.
Just a little biased I guess in that I feel 6000 mi is a nice number using regular oil.... that is non-synthetic.
Changed out the fuel filter.... I noticed at Cummins N.W. here in Spokane, they have a nice little note next to the fuel filters indicating that changing the filter out at every other oil change is " Cheap insurance for the life of the Bosch pump which is only $2400.00" Sounds like a deal to me.
Checked the diffs....Oil looked good, but there was a bit of very fine sludge on the magnetic drain plug. I'm hoping someone will say..." That's normal!"
Both the front and rear showed it.
Noticed a bit of weepage from the waterpump.... Normal?
And the Steering box looked a little wet... No sign of leakage... just some damp area... Not sure what that means....
Everything else is going great.... getting 17.4 mpg around town combined driving.... 20 at 65-70... Really can't complain.....

 

The little metal shavings and sludge on the diff drain plugs is normal, no need to worry. however i had seepage around my water pump and they had to replace it, under warranty. just make sure that they change out the thermostat or make sure they dont trip it. mine screwed up and took them 2 extra days to fix it