Just bought a new 2005 D/A dually last week. I have been researching on this site for a few answers to some of my questions but there are several opinions/answers to each question. These questions have been asked several times but as a new owner of a Duramax I would like to ask them all in one place. This is my first diesel truck experience.

I will be towing only about 5000 to 6000 pounds about 150 miles round trip approx. once or twice per quarter. I will use this truck as my daily driver.

1. Should I use a fuel additive year round? Or just in the winter? I live in Maryland, it gets cold Dec. through early March. The temp dips into the teens but rarely lower than that. Will adding a fuel additive year round help ensure that the fuel I use is of a high quality? (will it improve the quality of "bad" fuel?)

2. I have read that some owners get their oil/filter changed at under 1000 miles maybe even twice before 1000 miles on the truck. Should I do this? I don't mind changing the oil/filter frequently or changing it at intervals more frequent than the owners manual dictates.

3. When should I change the tranny fluid and filters the first time? Should I change it sooner than 25000 miles as I believe the owners manual states after the initial fluid and filter change to be on the safe side?

4. Should I buy fuel only at truck stops?

5. How concerned should I be about the overheating issue that is discussed in about 4 different threads?

Thanks in advance.

Most additives have lubricity and cetane boosters in them. These are good things...especially the lubricity booster, which will only help your injectors and pump stay as healthy as possible. The additive is not the end-all, do-all for avoiding fuel system problems but is a relatively inexpensive bit of insurance. Buy fuel from high volume dealers. That doesn't necessarily mean truck stops.

The oil change is up to you. Many change after the first 1000 miles and more often than recommended from there out. IMO, changing at 1000 and then 3000 and then 10000 is advisable before you start adhering to the recommended service interval. I've never let my oil life go below 50% according to the DIC. Perhaps just as importantly is that you swap out the fluid in the differential(s) BEFORE 1000 miles and refill with a high quality fluid that meets the required specs.

I'd change the spin-on transmission filter every 3000 to 5000 miles and swap out the fluid and internal filter no later than 25000 miles. The spin-ons are simple, relatively inexpensive and you top them off with fresh fluid. Heat is the killer of transmission fluid.

I would not sweat the overheating issue.

Congratulations on the truck and welcome the place.

Welcome the site!
and its addictive...

1. i have yet to run any diesel fuel additive and have had no problems and i live just south of you. when it gets cold, the best thing i found was to plug in the block heater when it gets real cold. lots of threads out there on that.

2. i have not read that anybody changes their oil filter at 1000 miles. maybe just the first time wouldn't be a bad idea. if you do it yourself, make sure you have a filter wrench that fits the filter (its big and GM has a gorilla that works at the factory to put the oil filters on).
other than that, i just go by the DIC as to when i change the oil which seems to be about every 10,000 miles (give or take).

3. I think the big thing on the tranny filter is the little red external filter. do a search on that one, thats what i did.

4. fuel at truck stops has a better turnover rate, less likely to grow mold or what ever it is that diesel grows in it after sitting around. this also means less likely to have any water in it i would think. big thing is to keep your fuel filter changed (about 10,000 would be a good guide i would say, thats about what i go with)

5. if you don't tow over 10,000 pounds at altitude going up long grades, you probably wont have a overheat issue.