Truck Classification

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Tinker, Jun 7, 2013.

  1. Tinker

    Tinker New Member

    I have just acquired a 2004 GMC Sierra SLE/Crew Cab/4X4/ Short Box/ 6.0L Vortec/4-spd auto trans. The question I have to ask is, is this considered a 1/2 ton or 3/4 ton. Please note: The truck is not badged as a 2500HD. The badges on the front doors simply say GMC2500.

  2. SupplySgt

    SupplySgt Rockstar 4 Years 500 Posts

    If it says 2500 on the badges then it should be a 3/4 ton. Check and see how many lugs are on the wheels. That will tell you real quick if it's a 3/4 ton or not. I want to say the NBS 3/4 tons had 8 lugs (I could be wrong as the OBS ones had 6 with the 1/2 tons having 5)
  3. Tinker

    Tinker New Member

    Thank you SupplySgt for the info.

    Truck has 8 Lugs, so it's a 3/4 ton..........higher on the back-end than a half ton too.

    I think it should be able to pull a 1990 26' Prowler Travel trailer with out to much trouble.

    Had insured the truck yesterday, my agent phones up and says her computer had "dropped some of the info about the truck" I had given her. Wanted to know if it I said it was a SLE or SLT, and if it was a 1/2 ton or 3/4 ton, so that was the reason for the classification post.

    What is NBS and OBS short for?

    Now if I can get the check engine light problem solved, I'll be a happy camper.

    Problem with light seems to be directly related to the gas cap. When the light comes on, and the gas cap is removed and reinstalled the light usually 9 times out of 10 will go out in about ten seconds.

    Took the truck to the dealer and they say that they think the cap is fine. I have put the cap on and thought it to be installed correctly. Then with just a thumb and forefinger lifted the cap off of the filler neck ( I had aligned the lugs on the cap to the filler neck and pushed down as the cap was turned for about 6 clicks).

    Even if the cap is on and can not be lifted off, the light will come on sometimes after about 1-1/2 hrs of running the vehicle or sometimes 3/4 of a tank of gas is used and the light will come on. Again, do the cap off/cap on thing....and the light will go out. Light has been coming on quite regularly in the 2 weeks I have had the truck. I myself think the cap needs replacement, as the locking lugs of the cap may be worn and allowing a leak or the vent in the cap is faulty. The computer had stored a code that was removed by the dealer and it was thought the "old code" was causing the light to come on...but the light came on the next day before I put more gas in the tank.

    Members input on this problem would be welcomed. Maybe I'm missing something.

    Thanks all

  4. McClintoc

    McClintoc ɹoʇɐɹǝpoɯ Staff Member 3 Years 1000 Posts

    OBS = old body style (before 1999)
    NBS = new body style ('99 to '06/'07)
    NNBS= new new body style ('07 and beyond; the current body style)

    I had to ask when I first got here, too. :neutral:
  5. j cat

    j cat Epic Member 5+ Years 1000 Posts

    the cap you have may be in need of replacement. or could be the wrong cap. the DTC code you should post. the system does check for vacuum/pressure during vehicle operation. if you have a small leak in the fuel tank or the vapor system / canister this is the other possible causes.
  6. nonnieselman

    nonnieselman Member 1 Year

    yep if there is any leak in the fuel system the EVAP isnt happy and throws a light.
    There is a pressure sensor on the top of the tank that tells the PCM if it has pressure or vacuum on it. It uses the vacuum from the engine to keep the fumes down. I cant rem the exact reading but it just keeps pressure from buildin up in the tank.
  7. j cat

    j cat Epic Member 5+ Years 1000 Posts

    the test does apply vacuum and measures for pressure as well. also the PCM will switch vacuum to the canister to purge out the vapor stored in it . if the canister is damaged or valves don't work correctly you will get the DTC to come up.
  8. stchman

    stchman Active Member 2 Years 1000 Posts


    From 1988 to 1998 the 2WD had 5 lugs and the 4WD had 6 lugs. In the same time period, all 2500 and 3500 had 8 lugs.
  9. h0serdude

    h0serdude Member

    You should be fine towing that trailer. Your truck is the same as mine and it's rated to 9900lb tow rating.

    edit: oops hit enter too soon
  10. dsfloyd

    dsfloyd Epic Member 5+ Years ROTM Winner 1000 Posts

    I also have the 2500 (non HD). Its a 3/4 ton and really isnt much different than the HD. The Towing capacity is slightly lower but should handle your towing needs.

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