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Chevy Silverado and GMC Sierra Duramax Diesel Questions



  • I just bought a 07 3500 crewcab dually in Dallas and took it to Toronto Ontario and got 22mph on the highway doing 75 on cruise.
  • My 05' has116000 and runs great.
    but my last trip,I kept it under 70mph the whole time and got less than 17mpg. The truck is stock from the day I bought it brand new. I would expect worse mileage when I have my tools in the truck,but this trip the truck was empty. If I wentv with a chip,what kind of problems or damage to my truck should I expect? anybody?
  • folbfolb Posts: 54
    My 05 has 93k. I have the Pacific Performance Engineering(PPE) OBD II programmer. I keep it on tune 3 out of 10. Seems the faster I go, the better mileage I get. 29 MPH on an hour and a half trip to DC. I changed the fuel rail valve to a PPE valve. I have experienced a trans problem because of too much power which puts too much pressure in the tranny lines. Bullydog and PPE have kits to put in the trans to prevent this but I haven't done that. I really only had trouble when towing thru the mountains. Easy to reset with the programmer though.
  • I am having this same problem. What was your fix?
  • barrailbarrail Posts: 27
    Here is my two cents, I have (diesel domination's ) duramileage ez tyuner . I've only experimented with the lowest ,2nd lowest and 2nd highest settings so far, and I haven't noticed much difference in mileage yet. I'm running a 6'-8' bed full of hand tools but not towing with it . all the settings seem to all but eliminate turbo lag but the weather has been to cold to get any decent mileage. So far, transmission seems to be working fine. Hope this helps in somesmall way.
  • gmcustsvcgmcustsvc Posts: 4,055
    Have you resolved the issues with your vehicle?
    GM Customer Service
  • Christina,

    GMC only wants to pay half to get my truck fixed. It will still cost me 2k-2.5K to get fixed!!! The truck only has 80K on it, GMC should pick up all the cost!!! I don't have 2K to fix the truck right now! This sucks!!!!!!

    Can you get me Dan Downings phone #? I would like to talk to him, my so called district specialist Jerrod at ext. 11060 is not so helpfull!!!

  • cls3cls3 Posts: 1
    Hello, Could someone give me some advice? I have ordered a 2011, shortbed duramax 4x4,crew c. I've been reading the posts about chips and realize that that's probably my best bet. I plan on pulling a 32 ft. 5th wheel but still will be doing every day driving without the 5th wheel. I'm concerned about effecting my warranty, creating trans. issues and selecting the correct chip/exhaust. Any suggestions would be appreciated. Thanks, CLS3
  • My truck is stock, can't help on the chip part.

    My advice would be not to buy the Duramax unless you want to change out your head gaskets at 80K miles! If you do buy get the extended waranty!!! Diesels are very expensive to fix!!!! Replace head gaskets 3.5K-4.5K to fix!

    As you can tell I'm not to happy with GMC right now! It is the end of February I have been dealing with this since the 1st of the year. It's been 2 months and I am finally suppose to ge my truck back today!!!!

    Good luck!!!!!
  • folbfolb Posts: 54
    I have a 2005 and love it. I put a PPE programmer on mine. It plugs into your OBD II reader. Nice thing about that is unlike a Banks system which is installed under the hood with lots of wires and such, you can unprogram it to take it in for service. My tranny can't take all the power though. Can only go to 3 out of 10. Better gas mileage too. PPE, ATS and Bullydog all sell some tranny upgrades for the slip issue under too much power. Haven't gotten mine yet tho.
  • I to have an 05' d-max and love it. It has been a stock truck up until 116,000 when I put a diesel domination programmer in it. The programmer offers options like trouble shooting engine codes, different tire size reprogramming, and its simple to install. If the truck has to go in for warranty, you reset the trucks settings back to stock. I have close to 4000 mi. with the programmer and, with the weather starting to warm up, I 'm starting to see my mileage improve slightly. Hope you have as much good luck with yours as I have.
  • buy it, take care of it, don't add a thing to it(after market), love it. The best truck I have ever owned. My 2008 diesel 6.0 4x4 3/4ton Sierra has been flawless in power and I pull a 25ft trailer in steep terrain with no problems. I've had some minor issues which were dealt with thru warranty.
    I would not add a thing to the motor or exhaust, for warranty reasons but also because it simply does not need it.
  • Leave it the way it comes! I have a 2007 Classic 3500 crew cab and I pull a 35ft fifth wheel in the mountains of Utah and Idaho. It comes stock with all the power you need you can pull your trailer faster than any one should on the flats uphill it doesn't matter. I know several people that have chiped there trucks and yes they do get power gains but all those full mileage increases that are written about on this and other sites I havn't found anyone that has actually gotten more than a few miles pre gallon gain. You can't drive yout truck far enough to ever offset the cost. Maybe that's why it seems some people over state the gains they have gotten.
    I love this truck I have just over 60,000 miles and no problems.
  • gmcustsvcgmcustsvc Posts: 4,055
    Please keep me updated on your situation.
    GM Customer Service
  • gmcustsvcgmcustsvc Posts: 4,055
    I'm happy to hear of your satisfaction with your truck. Please feel free to contact me if you have any questions, comments, or concerns.
    GM Customer Service
  • Christina,

    Got my truck back 2 weeks ago from the dealer (after they pulled the heads and sent them off to the machine shop and put it all back together). Drove it 10 miles to my work from the dealer and when I got to my work coolant was spewing all over the place. Had a flat bed truck come pick my truck up, couple of days later dealer calls me back saying it needs a new cylinder head. Waited a week for new cylinder head, dealer starts putting engine back together and calls me and says it needs new exaust valves in a couple of cylinders. Was told last week that I should get my truck back this week. I have been dealing with this since the end of December. The truck barely has 80k miles on it. The duramax diesel engine is a piece of crap!!!!!!!!!!!!!!!

  • barrailbarrail Posts: 27
    Slayersmith; sorry to hear your trucks giving you so much trouble. Besides myself, four of my friends have D-max's and have had very few problems. One 05' with the LLY has 350,000 with the original brakes on it. another 05' has 200,000 , but the chicago weather destroyed the fuel lines. that was a frame off to repair it. mine has a 121,000 with only regular maintaince. hope you get to the bottom of the problem. Does the repair shop work on D-max's very often? good luck.
  • Barail,

    My truck is an O3. I loved this truck before all the problems. The 80K miles I have on it are all long distance road miles on weekend trips. It's a good lookin truck. It's sits with a cover on it in my driveway during the week. I was told when I bought this truck that the engine would break in at 100K. Very disapointed with this truck.

    You might want to check out getting extended waranty, if you have to do any major work to the engine it is very expensive. Blown head gasket on the duramax is a 34 hour job at $100 per hour, you know what I'm saying! Thats just labor, parts are another 12 to 15 hundred bucks.

    I am lucky, I have a beater that I drive for work, If I did'nt, wonder how much a rental car would have been. Truck has been down now for 2.5 months at 40.00 per day = Doh!!!!!!!!

    Duramax = FAIL!!!!!!!
  • dixmaxdixmax Posts: 1
    Our 02 'Max" has 97k miles, mostly long distance. No internal problems
    'yet'. Wonder if a chip would be an option for better mileage and power at this point.
    I don't have the readout computer, but I keep exact "per mile", "per tank" records. I get 9-10MPG with 12k trailer, 17-18MPH solo around town.
    Anyone had any experience with the new 2011 "DEF" system? Reluctant to buy it.
  • gmcustsvcgmcustsvc Posts: 4,055

    My name is Michelle, I am assist Christina at this time. I have read over your correspondence with Christina. I can understand the frustration that you are going through with your situation.

    We would like to set up a case for you. Please, e-mail us the following information:
    -Your first and last name.
    -Your completely contact information and the best time for us to contact you.
    -The VIN of your truck
    -The current mileage that is on your truck
    -The name and location of the dealership that you have had the to for this issue

    Once we receive this information we will be able to set up a case.

    Michelle P., GM Customer Service (assisting Christina)
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