N14 with 3.91 gears, 10 speed. Change to what gear?

Discussion in 'Ask An Owner Operator' started by Asalinas2y, Sep 20, 2023.

  1. DUNE-T

    DUNE-T Road Train Member

    6,915
    16,732
    May 10, 2015
    Detroit, MI
    0
    You can up that to 430hp and get 3.55-3.58, you will be absolutely fine. 1500-1600 RPM at 70mph is good, below 1400 is not.
     
    Asalinas2y Thanks this.
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. DUNE-T

    DUNE-T Road Train Member

    6,915
    16,732
    May 10, 2015
    Detroit, MI
    0
    That is gonna be way more expensive than getting new rear ends. A reman 13 speed is $4000-4500, then you need a $3000 core, cut driveshaft, get new shifter and some other small parts.
     
  4. SmallPackage

    SmallPackage Road Train Member

    5,389
    16,948
    Dec 20, 2019
    Marion Texas
    0
    The key is letting the engine “breathe” let it work in a spot were it is not being force fed air and heat. Low manifold pressure is best. Running with the turbo spooled up all day just kills engines. I can cruise 1900 rpm at 65 all day and barely make 10 psi manifold 50 on fuel pressure and 600 degrees on pyro and get job done just fine. Rto 13 speed 4:11 rears. Still have plenty of throttle to get outa the way if needed.
     
    Dadetrucking305 Thanks this.
  5. abyliks

    abyliks Road Train Member

    3,810
    8,866
    May 2, 2010
    ludlow MA
    0
    I wouldn’t even waste money on a reman, it’s like $800 more to buy a brand new one with no core
    tower should be the same, it was under $1000 excluding the trans to swap the last one we did and we paid someone to do it
     
  6. DUNE-T

    DUNE-T Road Train Member

    6,915
    16,732
    May 10, 2015
    Detroit, MI
    0
    Oh wow, where did you see a new one for $5k? All I saw $8k and up for new
     
  7. abyliks

    abyliks Road Train Member

    3,810
    8,866
    May 2, 2010
    ludlow MA
    0
    $800 more then reman+ core
     
  8. KrumpledTed

    KrumpledTed Medium Load Member

    485
    1,463
    May 6, 2022
    0
    What CPL is the N14? What size tires are you running? The N14 isn’t one to pull down below 1500 RPM, they need to stay in that 1500-1900 RPM range to live a long, happy life.
     
  9. AModelCat

    AModelCat Road Train Member

    29,038
    156,701
    Jul 7, 2015
    Canuckistan
    0
    IMO if you're replacing the rear end strictly for fuel economy you're wasting your time. 7.3 mpg is very good fuel economy IMO. I doubt the gains you'll see will offset the cost for a very long time.

    Unless you've already got the carrier assembly laying around or you've got a lot of miles on that diff I would just run it as is until its time to replace.
     
  10. W923

    W923 Road Train Member

    1,332
    4,061
    Feb 28, 2022
    0
    If you’re really getting that mileage I wouldn’t touch a thing. Those Rpm won’t hurt it and as others have mentioned low rpm wears the main bearing caps making the block junk or very expensive to fix at overhaul time
     
    Dadetrucking305 Thanks this.
  11. Dadetrucking305

    Dadetrucking305 Heavy Load Member

    983
    2,583
    Sep 15, 2011
    Cibolo,Texas
    0
    Leave it be.That fuel mileage is very good especially on a non aero truck.Keeps the rpm’s up and doesn’t lug the engine.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.