Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Need Gear help...Not a "Gear Head"

Discussion in 'The Garage' started by brent c, Feb 2, 2006.

  1. brent c

    brent c Registered Member

    Joined:
    Nov 10, 2005
    Posts:
    7
    Likes Received:
    0
    Location:
    Texas
    Hey guys,

    Finishing up on a '70 K5 and want to add new gears to help move the 35" Nitto Mud Grapplers on Weld Racing 18" bad to the bone wheels! My calculations say 4.88's should do the trick; any advice one way or the other? 4.56 vs. 4.88 with a fresh 350?

    Also, if I order gears, what do I have to do to make the rear end "Posi-Trak".

    Dumb, I know, but not a gear head...sad.

    Any help appreciated,
    Brent at South Padre Island, TEXAS

    Hook 'em 'Horns!!!
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

    Joined:
    Mar 24, 2004
    Posts:
    3,069
    Likes Received:
    0
    Location:
    Ann Arbor Mi
    what tranny are you running?
     
  3. OffRoad

    OffRoad 1/2 ton status

    Joined:
    Dec 8, 2002
    Posts:
    852
    Likes Received:
    0
    Location:
    New Brunswick, Canada
    with a fresh 350, i think you'd be fine 4.56s if you do trails and mud. if you do rockcrawling, go with 4.88s.
     
  4. mr_blasto

    mr_blasto 1/2 ton status

    Joined:
    Nov 8, 2004
    Posts:
    495
    Likes Received:
    0
    Location:
    Irvine, CA
    4.88's or 4.56's will work fine. If you have an OD transmission go with 4.88's, if not you may want to consider 4.56's. Here is a nice calculator to play around with gear ratios:

    http://www.dfw-tx4wd.org/Tech-Dept/Tech-Dept/gears.html

    As for a posi... are you looking for a locker or a limited slip differential. Figure out what your looking for, then buy one, and install it or have someone install it.

    If you happen to have a d44 front and 12 bolt rear axle, I have some 4.88's with master install kits new in the box that I am no longer going to be using (I am going to 1-ton axles). Let me know if you are interested.
     
  5. trailblazr81

    trailblazr81 1/2 ton status

    Joined:
    May 27, 2005
    Posts:
    931
    Likes Received:
    0
    Location:
    Hollister, CA
    I have run 4.56's with 35" tires with a TH350 and 700R4. I wouldnt do the 4.88's unless I had the OD. And then I dunno cuz the 700R4 has the deaper 1st gear to get you out of the hole so its not needed. For "posi" look at an Auburn or Eaton limited slip. What you ar doing is replacing the carrier (its what the ring gear bolts to.) Posi is Chevy's name for limited slip which uses clutches to limit wheel spin. Some use hellical gears. They do about a 70/30 split and can wear out or be overpowered. They need some resistence to work. Myself and many others will sugest you get a detroit locker tho. :waytogo: It uses gears to lock the wheels and give a 50/50 split whenever power is applied.
     

Share This Page