Thread: Gearing: 3.73 to 4.10 or 4.56?

  1. #1
    Join Date
    Oct 2007
    Location
    Playa del Carmen, Quintana Roo
    Posts
    591

    Default Gearing: 3.73 to 4.10 or 4.56?

    My '99 Ford is currently geared with 3.73 gears (Dana 44 front and 60 rear, I believe) and I am running 33" tires. The overdrive shift points are a bit jacked due to the tire size and I am looking at having it re-geared. I'm curious as to whether or not going to 4.10's will make a reasonable difference? I know 4.56's will make it strong off the line but I am very concerned about highway performance, high RPM's and fuel mileage.
    Also, as far as I can tell there is no available gear ratio between 4.10 and 4.56 with my differential setup.
    Thoughts, experiences?

    Thanks for you time and knowledge-

    -Gary Mc
    "I don't believe in doing work that I don't want to do in order to live a life that I don't want to live."
    -Ed Abbey

  2. #2
    Join Date
    Sep 2009
    Posts
    937
    4.56 would be overkill for 33s, especially if you're trying to preserve highway performance. 4.10 would be the sweet spot, and be sure to throw in a pair of lockers while you're in there.
    '08 Range Rover Supercharged - work in progress
    '00 R50 Pathfinder - low and locked
    '85 Ford Wrangler CJ7 - 351 and 9in axles

  3. #3
    Join Date
    Mar 2009
    Posts
    1,699
    What engine do you have and how much weight? I have never heard anybody say they wish they had put in higher gears than they have but have heard a hundred times they wish they would have gone lower. 4.56 would be nice but 4:88 will pull a 35 when you make the swich to them someday or handle a heavy load real nice now if you don't have a v10 or diesel.
    Arizona

  4. #4
    Join Date
    Oct 2007
    Location
    Playa del Carmen, Quintana Roo
    Posts
    591
    How did I forget to forget to include the engine specs?!? It's a 5.4 liter Triton V8. The van is being built as a lighter version of a Sportsmobile. The only thing I ever tow is my raft and with it fully loaded and on the trailer it's about 3500lbs total.
    As far as 35's go.... No way in Hell will I ever go to a tire that big. I just don't need or want that. 33's suit my purposes just fine.

    Thanks-

    Gary Mc

    Quote Originally Posted by Stumpalump View Post
    What engine do you have and how much weight? I have never heard anybody say they wish they had put in higher gears than they have but have heard a hundred times they wish they would have gone lower. 4.56 would be nice but 4:88 will pull a 35 when you make the swich to them someday or handle a heavy load real nice now if you don't have a v10 or diesel.
    "I don't believe in doing work that I don't want to do in order to live a life that I don't want to live."
    -Ed Abbey

  5. #5
    Join Date
    Aug 2010
    Location
    Various places
    Posts
    694
    For a modern gas motor with an overdrive automatic transmission, I'd go for the 4.56 with 33's. My last truck came from the factory with 4.10 and 31's and was about ideal, and it didn't run at high rpm, even at 80mph. If you think the 3.73 isn't right, the 4.10 probably isn't a big enough step. Mileage difference between 4.10 and 4.56 would be minimal, and may not worse than the 3.73 as the transmission will be able to go into overdrive at lower speeds, and be more able to stay in OD while going up minor hills.

  6. #6
    Join Date
    Jan 2007
    Location
    AVL, NC
    Posts
    3,867
    I agree, 4.10's will only give you ~200 RPM. The 5.4 will love the 4.56's.
    Chris Steuber
    02 E350 7.3 V4
    11 E350 5.4 V5
    99 E36 M3
    www.ujointoffroad.com
    4x4 Van Conversions

  7. #7
    Join Date
    Jun 2010
    Location
    Kamloops, BC, Canada
    Posts
    129
    A lower gear ratio can save fuel at every point on the map up to, but not past, the appropriate engine RPM in the highest tranny gear.

    And yes..the "Cammer" motor, the Triton 4.6/5.4 are not the same as the older V8's...they need to rev a bit more before they wake up or even run "efficiently"
    Coming soon...backcountryvans.com

    -Serving the ASTRO & SAFARI Van
    -Solid UHMW Polyethylene Sub-frame spacers (body lift)
    -Steel Axle Spacers (lift blocks) with integrated Traction Bar (anti-spring wrap/wheel hop)
    -Bump Stop Spacers
    -Steel Off-Road Tubular Bumpers

  8. #8
    Join Date
    May 2009
    Location
    The Big Mitten
    Posts
    21
    Try this link it may help you figure out the ratio that works best for you.

    http://www.teammfactory.com/gearcalc...ission+1+%26+2

  9. #9
    Join Date
    Feb 2009
    Location
    Inland Empire, California
    Posts
    46
    Gary:

    I just regeared my 07 E350 and may be able to offer some info for you. I went from 3.73 R&P with stock 29" tires to 4.30 R&P with 33" BFG All Terrains.

    After the installation I'm seeing exactly the same engine RPM at 70MPH as I did with the original gearing and tires. I measured the speed using a GPS to avoid any speedo errors.

    Like you I am not planning on loading the van too heavily or doing any significant amount of towing.

    Hope this helps,
    Andy

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •