User Tag List

Results 1 to 4 of 4

Thread: Overdrive?

  1. #1
    Newbie
    Join Date
    Jul 2009
    Location
    Adamsville
    Posts
    4

    Branch
    Army Reserves
    Status
    Serving
    Served
    1984 to Present

    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Cool Overdrive?

    Is there anything that is like and extension to my auto tranny that will serve as an overdrive? I have heard of two speed transfer cases....would this act like an overdrive?
    I use my toy for mainly highway use but still want it trail capable. My fuel mileage is so aweful that you cant enjoy it.

  2. #2
    G.I. Grandpa SGM O's Avatar
    Join Date
    Apr 2009
    Location
    Monument
    Posts
    2,616

    Branch
    Army
    Status
    Retired
    Served
    1978 to 2014

    Closest Installation

    USAF Academy
    Mentioned
    1 Post(s)
    Tagged
    1 Thread(s)

    Default

    Your transfer case is a two speed. 1:1 and 2.72:1 assuming you have a stock case. There is a kit for automatics that acts as a doubler that fits in the auto tranny that would then give you 1:1, 2:1, 2.72:1 and 5.44:1 but none of these will help you on the highway. I have not researched an overdirve kit for a Jeep, but what you want is a way to drop your final gear in the transmission below 1:1. .9:1 would be considered overdrive. The issue then becomes do you have the torque/hp to maintain highway speed at the rpm the engine will be running at. An engine is most efficient at a certain rpm, say 2,000 - 2,200 rpm for the 4.0L six cyl, which should be about 60 mph. You could change the gears in your axles. They may taller gears, lower number, not sure what you have now, but most of us are going the other way because we want to run bigger tires and maintain our on street performance. You could try running one size larger tire. If you are running 235's try going up to a 245 or if they are 30" try running 31", this should not require any change in suspension, but your speedometer and odometer will be off slightly so to get an accurate mpg reading you will need to change your speedo gear or use a gps to calculate your mileage.

  3. #3
    F it! It ain't my Jeep. Ricky Booby's Avatar
    Join Date
    Nov 2008
    Location
    St Robert
    Posts
    1,386

    Branch
    Army
    Status
    Serving
    Served
    2000 to Present

    Closest Installation

    Fort Leonard Wood
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    I hate to be the nag here, but we need more info. What type of Jeep, tires, gears, motor, tranny, etc. Then you may get the advice narrowed down a little more.

    Bobby
    www.pnwjeep.com

    Quote Originally Posted by Walter View Post
    Alcohol, Tobacco and Firearms should be a convienent store, not a government agency.

  4. #4
    See Ya There!! Shadow's Avatar
    Join Date
    Jul 2009
    Location
    Choteau
    Posts
    244

    Branch
    Army
    Status
    Served
    Served
    1987 to 2004

    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Default

    Does your tranny have OD? If it does then that would/should give you .65:1. A splitter will only give a lower gear ration not a higher. How many miles on the clock? Any shifting issues, does 1st to 3rd shift correctlly? When was the last time the fluid was changed? Then there is the engine itself, does it smoke, knock, leak? Whens the last time you replaced the plugs, plug wires, cap and rotor?
    2003 Rubi with 6" lift rolling 37's w/ beadlocks, armor for effect. Constant state of change, its a jeep thing!!

    SOLD - 5.9 Grand with TNT Long Arms, KM2's, HP30 w/ARB & WJ Brake Conv., Rear 44HD Trussed & Skidded, 231 w/SYE, TW Drive Shafts & Custom Sliders

    RIP: 2004 Rubi: 3" lift on 33's

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Get the MJ Supporter Membership for a little less than $0.06 a day and get more space, 2 MJ Stickers and no banners ads. [Check it out]