30,000 service

timk49 · January 23, 2004

My03 2500HD 4x4 with the 6.0 passed the 30,000 mile mark last week and I finally got the chance to have some service work done on it today. I have been useing Mobil 1 in the engine and Wix oil filters since the first oil change at 3000 miles. The engine doesn't use oil and runs really good. I do tow a travel trailer over the mountains to the desert in the winter and to the mountains in the summer. The grades are steep The load isn't over what the truck is built to haul but I know it works hard especially in the hot summer months.

Today I had the transmission power flushed. I watched as the technician put 22 quarts of Castrol Dexron III Mercur into the machine and as the fluid began to circulate into the transmission I saw the dark dirty fluid running back out .He connected the machine to the trans cooling lines that connect near the top of the radiator. The whole flush took about 30 minutes. I already had six quarts of Mobil 1 for the engine and the Tech drained the engine oil and added tne new oil and filter for no extra charge.

What else needs attention? Should I have the Transfer case or differentials serviced and if so with what?

Of course I have the K&N drop in and I keep it clean I also grease the front end myself so I know thats good.

After the service I believe I can feel a difference in the shifts. In tow haul mode they feel smoother not as abrupt as before. I attribute that to the synthetic fluid.

Is the next milestone 60,000 miles I assume that is when the trans gets another flush.

JimWilson · January 23, 2004

A flush every 30K is on the obsessive side, but if you tow a lot you can certainly justify it. Me, I run M1 in everything, so I only do it every 50K. You could get away with that interval using a good quality ATF too.

My personal preference is to do the entire driveline at once, so when I did the tranny I also did the tcase and the front & rear diffs. The rear diff is a piece of cake. The tcase is pretty easy too. The front diff is a PITA, but doable. I just went and bought a bunch of M1 and took my time.