I've had my 03 duramax LB7 for about 3 months now and i've just changed my engine oil. I also had my dealer to replace the recalled fuel filter at the same time. And if that wasn't enough, my shifter was loose and leaked 1.5 qrts of ATF fluid out, So i went ahead and changed it also (ZF/6).

Now that i'm running all new oil and filters, my question is this; I would rather change the oil/fluid/filters based upon hours instead of miles. This is because my job requires me to go from job-site to site, and customers shop. Therefor, i may put 3 hours on my truck and only go 40 miles or so.
Anyway, what recomended HOURLY interval do some of you guys think on things like oil/filter change, fuel filter change, front/rear axles, and transmission/transfer case oil? I have 1800 hours/62,000 miles on it now.
Thanks

I just asked the same question of the tech line at amsoil. how may hours can I go and they recomended 650 hours between oil changes ( theirs being a 25,000 mile interval).the formula is 40 miles per hour times the oil change inteval of the oil.

I've had my 03 duramax LB7 for about 3 months now and i've just changed my engine oil. I also had my dealer to replace the recalled fuel filter at the same time. And if that wasn't enough, my shifter was loose and leaked 1.5 qrts of ATF fluid out, So i went ahead and changed it also (ZF/6).

Now that i'm running all new oil and filters, my question is this; I would rather change the oil/fluid/filters based upon hours instead of miles. This is because my job requires me to go from job-site to site, and customers shop. Therefor, i may put 3 hours on my truck and only go 40 miles or so.
Anyway, what recomended HOURLY interval do some of you guys think on things like oil/filter change, fuel filter change, front/rear axles, and transmission/transfer case oil? I have 1800 hours/62,000 miles on it now.
Thanks

Using hours is appropriate for your engine (oil, fuel, air), and possibly for your transmission, but would not be appropriate for the transfercase or axles. You'd be best to use miles on those.

In almost two years of driving (mostly city miles) my average speed is very close to 30 miles an hour.
~37,000 miles
~1,200 hours

Now that i'm running all new oil and filters, my question is this; I would rather change the oil/fluid/filters based upon hours instead of miles. This is because my job requires me to go from job-site to site, and customers shop. Therefor, i may put 3 hours on my truck and only go 40 miles or so.


If you idle a lot then you'll want to change it more often. My cumulative average speed is 38mph, and i change every 3000 miles, which is only about 80 hours. I thought about going by hours and changing at 100, but there is this bug in me that won't let it go past 3000 miles. If you don't have that bug, I would say 150 hrs would work.

i thought about every 100 hours on oil/filter, 200 hours on fuel filter - this may sound like close intervals, but without no other filtration right now, and sensitve duramax injectors, id rather be safe than sorry.