Can it be this good now??

[johnpugh]

I am just getting used to my 2 week old 2003 DMax/zf. According the the mileage computer I am averaging 15.9 mpg and I only have a few hundred miles on it. This is city driving only. If its getting this now, can it get better?? This already beats my old 99 1500 with the 5.3. I guess I should do a manual calculation at the next fill-up, but I figure the computer should be accurate enough. Also, when I did get it out on the tollway, my instantaneous mileage was hovering in the mid to upper 20's (at 65mph).

All I can say is this truck is awesome.

Also, my truck does NOT have a cat in the exhaust. I thought all 2003's got the kitty, not that I am complaining.

It's hard to wipe the smile from my face.....

[txguppy]

Congrats on your new Duramax. Your mpg is pretty good, although it should be a little better than that w/ the ZF. I know it's hard to keep your right foot under control. :D Don't baby her, she needs to be revved-up occasionally. Also, it's better to "warm her up" by driving 30-40 mph than to let her idle up to temp. You should see a substantial mpg increase around 24k. My brother just an '03 and Dad has an '02 so we got all 3 year models to compare. Those GM guys are really getting pinche.
:(

txguppy

[polaris800]

Im not convince that these instruments work very well. The last to times I compared the actual milage from the computer and them did it manual and found that it was not correct. My 03 will not heat up properly and has been to the shop twice and both thermostats have benn replaced to date. Now they said they were ordering a new valve. Not sure were this is on the truck but it might fix the problem. My milage has not been good either 12 to 14.5 hopefully this is due to lack of break in period. Has 4500 miles and is a crew cab 8' box purchased three months ago. My 2001 took about 8500 miles before it got 15 in the city and 18/19 on the highway.

[johnpugh]

TXGuppy:

I do nurse it when cold, keep the revs below 2000 and try not to lug it. When it is warm though a little romp on the 'diesel' pedal is occassionally called for.... smile.gif

Polaris800:

Sorry to hear about your problems. I have been following them in another thread. Mine does take a while to warm up, but within about 6-8 miles (depending on the outside temp) it settles in at about 185 to 190. Actually, I can watch the thermostats open on the temp guage. The temp will get close to the 210 line, then all of a sudden it will start dropping and settle out. Hopefully, the T-Stat changes will fix your problem as far as temp is concerned.

Still smiling..... :cool:

[kerry witherspoon]

polariss 8oo what dealer in calgary are you using

[amcgibbon]

JMPDMAX...

What do you think of the ZF? Does it shift smooth? Is the clutch nice and smooth? I would appreciate any comments that you have as I have a new truck on its way.. Thanks..

:(

[MaxACL]

JMPDMax
The ZF will smooth out a bit when you log some miles. But, on a sour note, the shifting pattern is terrible. While under a load and starting at a light on an incline, it's easy to miss 2nd as the trek from 1st to 2nd is a mine field. And on more than one occasion, (when starting from a stop without a load) I have slid into reverse instead of 2nd. Now I'm paranoid and wont relax till I feel forward motion.

Mike :D

[johnpugh]

amcgibbon and MaxACL:

Yeah the shift pattern is kinda quirky. That 1-2 shift can be a real cliff hanger, especially in traffic around Dallas. After the initial 500 miles is up, I expect to do most of my launching from 2 not 1, unless loaded or on a steep incline.

As far as the overall operation goes, I could not be happier. The clutch is smooth and the shifting for the most part has been smooth also. I've only had to double clutch a couple of times and those were at stoplights, where I usually let it sit in neutral with the clutch out (to save wear on the throwout bearing).

Still smiling in Dallas... :cool:

[George Gozelski]

What are you guys even using 1st gear for?

[johnpugh]

George:

Per the manual, you are supposed to use first gear for launching for the first 500 miles. The manual states that the reason is to ensure proper wear-in of the clutch materials.

[amcgibbon]

Thanks to all who helped me out with comments on the ZF. I need to be reassured that I am not getting into a subpar tranny for a $37K truck.. Thanks..

[Nels]

Getting back to the topic of your mileage -
I had numbers close to that during the break-in period as well. As was stated above, it gets better as the engine loosens up. Mine has 31,000 miles on it now. I took a trip to Southern Iowa and back yesterday and averaged 21 mpg (on winter blend fuel) on the return trip, averaging 65.7 miles per hour for the last 447 miles (nonstop -- not even to pee, except for three toll booths). I made it from Osceola IA to Manitowoc WI in 7-1/2 hours. Full records are in the spreadsheet below.