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Better fuel economy with front output shaft (drive shaft) removed?

Discussion in 'General Chevy & GM Tech Questions' started by Family Force 6, Jun 25, 2013.

  1. Family Force 6

    Family Force 6 Rockstar 100 Posts

    Riddle me this..

    Getting ready to do 1200 miles on my 99 suburban with a NP246 auto-trac transfer case. I have the front drives shaft out now to get a u-joint replaced which got me to thinking. Would I see an increase in fuel economy if I left it out for the trip? The front output shaft spins constantly with the auto-trac transfer case, however I understand that there is no "power" being sent to the front wheels.

    And yes, I'm doing most of the basic tune-up stuff right now that will REALLY make a difference, including:

    New O2 sensors
    New distributor cap/rotor
    New air filter
    Oil change
    Seafoam throttlebody treatment
    A/C fixed (yea for A/C!)

    I can't think of any reason why I would need to have it in.
    Last edited: Jun 25, 2013
  2. K15 Blazer Guy

    K15 Blazer Guy Member 2 Years 100 Posts

    I would say no... plus it could mess with the transfer case... your allowed to shift into 4WD up to 25mph and if the front input/output is not spinning like it should be the computer could have a fit

    best way to boost your MPG is an intake, and delete the mechanical fan for a good electric one.
  3. Family Force 6

    Family Force 6 Rockstar 100 Posts

    I've been looking at a couple threads on installing an electric fan. I'll continue to investigate, but not sure I'll be able to tackle that before we leave.

    I've heard mixed things about the benefits of an air intake. What's your experience been as far as fuel economy gains and what brand did you use?
  4. K15 Blazer Guy

    K15 Blazer Guy Member 2 Years 100 Posts

    I got a simple K&N intake. not the big tube 57 series.

    IMG_0126.jpg
    this works best for my old engine. i gained HP and MPG (one more than the other depending on how i drive)
    also lets me hear the engine better too.

    as for the fan

    http://www.gmtruckclub.com/forum/showthread.php/124193-electric-fan-mechanical-replacement/page3

    I put mine in, in an afternoon.
    with a 160 thermostat it runs perfect, even with the noticeable gap between the fan and the stock shroud.
    i may cut an inner tube to fill it later though.... but for now, its fine. i don't even run it when im at highway speeds

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