1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

What Turns in a 4x4 in 2WD to Reduce Mileage?

Discussion in '2nd Gen. Tacomas (2005-2015)' started by SManZ, Jan 8, 2010.

  1. Jan 8, 2010 at 4:22 AM
    #1
    SManZ

    SManZ [OP] el tráfico más lento se queda derecha

    Joined:
    Sep 15, 2009
    Member:
    #22817
    Messages:
    1,354
    Gender:
    Male
    Haymarket, VA
    Vehicle:
    '10 Supercharged 4x4 Sport 6-spd
    TRD Supercharger, King 2.5" extended travel remote-resi coilovers, OME Dakar leaf packs, King 2.5" extended travel rear shocks, Total Chaos UCAs, MBRP turndown exhaust, TRD intake, TRD Quickshifter, Goodridge SS brake lines, EBC Sport Rotors, Hawk HPS pads, TRD FJ Cruiser Special Edition 16" Anthracite Rims, Spidertrax wheel spacers, 265/75R16 A/T, Autometer oil pressure, oil temp gauges, TRD boost gauge, PLX DM-100 OBD II scanner, flexpod mounts, A-pillar gauge pods
    I searched this forum and Google and couldn't find the answer...

    What turns in a 4x4 Tacoma when its in 2WD that causes the mileage hit over a PreRunner? This is my first 4x4 so I don't fully understand how it works yet.

    I took a look under the truck and I think that the front wheels turn the front driveaxles whenever the truck is moving? More rolling resistance? There is a boxy assembly with a large electrical connector at the transfer case and I'm guessing that is where the front driveline is engaged when the 4WD switch is turned.

    How is the setup in the Tacoma different from the older 4x4s where you would have to get out and lock the hubs?

    -Thanks!
     
  2. Jan 8, 2010 at 4:42 AM
    #2
    misterquad

    misterquad Well-Known Member

    Joined:
    May 12, 2009
    Member:
    #17118
    Messages:
    501
    The 4x4 consumes more gas because it carries a transfer case and front differential for extra weight. And since we don't have locking hubs, the front differential and axles are spinning all the time which consumes more fuel too. Locking hubs can be unlocked with the transfer case in 2wd and the front axles and differential stop spinning all the time.
     
  3. Jan 8, 2010 at 5:13 AM
    #3
    SManZ

    SManZ [OP] el tráfico más lento se queda derecha

    Joined:
    Sep 15, 2009
    Member:
    #22817
    Messages:
    1,354
    Gender:
    Male
    Haymarket, VA
    Vehicle:
    '10 Supercharged 4x4 Sport 6-spd
    TRD Supercharger, King 2.5" extended travel remote-resi coilovers, OME Dakar leaf packs, King 2.5" extended travel rear shocks, Total Chaos UCAs, MBRP turndown exhaust, TRD intake, TRD Quickshifter, Goodridge SS brake lines, EBC Sport Rotors, Hawk HPS pads, TRD FJ Cruiser Special Edition 16" Anthracite Rims, Spidertrax wheel spacers, 265/75R16 A/T, Autometer oil pressure, oil temp gauges, TRD boost gauge, PLX DM-100 OBD II scanner, flexpod mounts, A-pillar gauge pods
    Thanks guys! The Toyota website does say the curb weight of the 4x4 is 235lbs more than the PreRunner (4045 vs 3810lbs). Too bad hubs aren't available for the 2nd gen Tacomas so the front axles don't have to freewheel all the time. I'd think we'd get a little better gas mileage.
     
  4. Jan 8, 2010 at 5:37 AM
    #4
    Zombie Runner

    Zombie Runner Are these black helicopters for me?

    Joined:
    Mar 13, 2008
    Member:
    #5246
    Messages:
    15,036
    Gender:
    Male
    First Name:
    Kevin
    Wichita Falls, TX
    Vehicle:
    Tundra, double cab.
    LED interior lights, stubby antenna, Pioneer in dash screen, good driver mod.
    The pre runners are heavier than 3810 lbs. I had mine weighed with an empty tank and all the extra stuff removed. i.e spare tire, tools, etc.. and it was right around 4100 (IIRC)
     
  5. Jan 8, 2010 at 5:56 AM
    #5
    misterquad

    misterquad Well-Known Member

    Joined:
    May 12, 2009
    Member:
    #17118
    Messages:
    501
    My last trip out we were loaded at 5,600#s.

    The best bet for mileage improvements is light skinny tires. In my other trucks I cannot say that hubs made as much of a difference as tires do.
     
  6. Jan 8, 2010 at 7:19 AM
    #6
    putawaywet

    putawaywet Yaris Offroader

    Joined:
    Dec 16, 2009
    Member:
    #27670
    Messages:
    79
    Gender:
    Male
    First Name:
    Jason
    New Hampshire
    Vehicle:
    '10 4x4 Access Cab V6 6MT Black Sand Pearl
    USA-SPEC iPod interface; bed liner; more to come...
    I did a search and couldn't find anything - is it even possible to convert a 2nd gen to manual hubs?
     
  7. Jan 8, 2010 at 7:50 AM
    #7
    Janster

    Janster Old & Forgetful

    Joined:
    Mar 25, 2007
    Member:
    #1138
    Messages:
    14,256
    Gender:
    Female
    First Name:
    Jandy
    Lancaster, PA
    Vehicle:
    2016 GMC Canyon SLT w/ LineX and....
    If you put a solid axle under it. :D

    SManz - you won't notice any gas mileage improvements simply by stopping the rotation of the front axle shafts. The only thing that really does is prevent wear/tear on the front axleshafts & bearings.
     
  8. Jan 8, 2010 at 8:49 AM
    #8
    kilgoja

    kilgoja Well-Known Member

    Joined:
    Jun 20, 2009
    Member:
    #18685
    Messages:
    592
    Gender:
    Male
    Alabama
    Vehicle:
    2009 regular cab 4x4 2.7L (silver)
    :mudding:
    that's why i got a regular cab 4x4 with the 4cyl....best of both worlds
     
  9. Jan 8, 2010 at 8:50 AM
    #9
    jscrub

    jscrub Active Member

    Joined:
    Jul 16, 2009
    Member:
    #19739
    Messages:
    28
    Gender:
    Male
    The Truck has to spin 4 wheels instead of 2. More rotational mass is probably the key cause not including the added weight and kinetic energy loss through added mechanical components.
     
  10. Jan 9, 2010 at 5:18 AM
    #10
    misterquad

    misterquad Well-Known Member

    Joined:
    May 12, 2009
    Member:
    #17118
    Messages:
    501
    Correct me if I am wrong, I believe the Tacoma hubs are always locked it is the transfer case that disconnects. :confused: Thus, the wear marks on the CV boots?

    Anyway, of all my 4x4s I like the Toyota hub system the best. I use shift on the fly in the rain while on the street. If I am entering a wet corner I will shift into 4wd to go through it. That eliminates that inside wheel spinning on wet asphalt.

    Being an old guy :D But I am listing the different setups I had in order of preference:

    1. Continuously locked hubs because I use shift on the fly 4x4 on the street during slick conditions.

    2. Manual locking hubs are next choice because I will lock the hubs in when I think I may have slick conditions that day, month, etc.

    3. Auto locking hubs like Ford used on their 1990's pickups just sucked IMO. They never engaged unless you were moving. I got stuck on ice at a stoplight in Michigan and 4wd would not engage because the rear wheels spun and the truck would not move to engage the hubs.
     
  11. Jan 9, 2010 at 10:48 AM
    #11
    FLtaco4x4

    FLtaco4x4 Member

    Joined:
    Dec 13, 2009
    Member:
    #27462
    Messages:
    20
    Gender:
    Male
    DC's weight a lot more than the Xcabs or Reg cabs too.... just a note. They don't differentiate the MPG difference, between the cabs. just the engine and trans/drive. So according to the EPA & Toyota the reg cab vs DC long bed doesn't make a difference.... right. I'm sure theres quite a bit of extra weight. 4cyl 5spd Xcab 4x4 my friend...
     
  12. Jan 9, 2010 at 4:15 PM
    #12
    bsfarmer

    bsfarmer Member

    Joined:
    Jan 9, 2010
    Member:
    #29049
    Messages:
    13
    Gender:
    Male
    First Name:
    Brad
    Dixon, IL
    Vehicle:
    2008 Base Model 4x4 Access Cab
    265/75/16 TSB rear
    These are not auto locking hubs, they are drive flanges. It is much similar to the Toyota's of the 90's, they have a disconnect at the front diff.
     
  13. Jan 10, 2010 at 6:13 AM
    #13
    FLtaco4x4

    FLtaco4x4 Member

    Joined:
    Dec 13, 2009
    Member:
    #27462
    Messages:
    20
    Gender:
    Male
    Correct bsfarmer. the CV is flange bolted to the front hub/wheel with no disconnect. The only real advantage of having manual hubs is if you break something, like say the front Ring & Pinion you can still drive home:) Ask me how I know this....
     
  14. Jan 10, 2010 at 6:46 AM
    #14
    magog45

    magog45 Well-Known Member

    Joined:
    Dec 1, 2009
    Member:
    #26811
    Messages:
    455
    Gender:
    Male
    Canada, just south of Santa
    Vehicle:
    98 tacoma 4x4 extended cab
    5100's all around, 2 inch lift, polyurethane body mounts, gibson exhaust, variation of the deckplate mod, intake resonators removed
    One thing that affects the mileage in a 4x4 is the gear ratio, taller gears for a 4x4 mean less mileage. I know on my 89 Jimmy locked verses unlocked was about 2mpg which was more than 10%, but from looking at the cost, time and effort of an aftermarket conversion its probably not worth it. Personally I think manual hubs should be standard equipment on all 4x4's and those that feel they need a 4x4 to negotiate the odd wet road or thick covering of leaves in their driveway can order the automatic ones.
     
  15. Jan 10, 2010 at 6:56 AM
    #15
    JDCPA

    JDCPA Well-Known Member

    Joined:
    Nov 15, 2008
    Member:
    #10777
    Messages:
    936
    Gender:
    Male
    First Name:
    Jim
    SW FL
    Vehicle:
    09 5 Lug Access Cab SR5
    Curt Hitch and etrailer.com wiring harness.
    Licking hubs are also not going to release when you need them the most like many self-locking hubs do.
     
  16. Jan 10, 2010 at 8:36 AM
    #16
    Janster

    Janster Old & Forgetful

    Joined:
    Mar 25, 2007
    Member:
    #1138
    Messages:
    14,256
    Gender:
    Female
    First Name:
    Jandy
    Lancaster, PA
    Vehicle:
    2016 GMC Canyon SLT w/ LineX and....
    To get more technical...and more for offroading situations.

    There are more advantages to having manual hubs.
    They prevent wear/tear on the front driveline components (bearings, gears, etc) by not running them constantly.

    If you have a locker in the front & it's engaged - you can unlock one side (hub) at a time to help with turning, prevent breakage, gain more traction to one side....etc, etc, etc.

    Besides all that... manual hubs are easier to maintain & repair when things fail.
     
  17. Oct 4, 2010 at 1:06 PM
    #17
    David K

    David K Well-Known Member

    Joined:
    Jun 27, 2009
    Member:
    #18969
    Messages:
    9,993
    Gender:
    Male
    San Marcos, Alta California
    Vehicle:
    2010 4WD Off Road DC
    Differential Breather Mod Light Bar: 2 Hella 4000 HID, 1 Cibie Halogen. Bilstein 5100s Ride Rite Air Bags
    Yes, you are correct... what I thought were called auto. locking hubs (from my old Jeep days with auto. locking hubs) is really called an ADD (auto. disconnecting differential) and by disconnecting one of the half axles from the differential, the differential and front drive shaft does not rotate when the front tires rotate when in 2WD.
     
  18. Oct 4, 2010 at 1:24 PM
    #18
    Monkeysuncle

    Monkeysuncle My Cat's breath Smells like Cat Food

    Joined:
    Aug 27, 2008
    Member:
    #8809
    Messages:
    1,248
    Gender:
    Male
    First Name:
    Kevin
    Florida
    Vehicle:
    99 Tacoma SR5 4x4 5 speed Manual Hubs
    Diff Breather,CB thingy,GPS,Cop Shocks,Cop Breaks, old Man Emu 881's Dakar Leaf Springs and Nitro sport shocks. Deck Plate mod
    Man, I do love my 1999 with manual hubs.
     
To Top