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Gear question

Discussion in 'The Garage' started by BNeu, Jul 31, 2003.

  1. BNeu

    BNeu Registered Member

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    Well i got my truck all lifted with 35 and now my buddy just gave me some 4.56 gears for free since he sold his truck. I was wondering if i should put them in. This truck is my daily driver and i was wondering what this would do performance wise and gas wise /forums/images/graemlins/eek.gif
     
  2. BlueKnight

    BlueKnight 1/2 ton status

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    some decent rpms with 35's. you might lose a point on gas mileage but your wheeling performance will be nice. I ran 456's with 38's and it was nice. Im running 5.13's now
     
  3. kennyw

    kennyw N9PHW Premium Member

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    Performance and gas mileage with 35" tire and 4.56 gears should be about the best you can get /forums/images/graemlins/thumb.gif But that is also going to depend a little on what tranny you have and how you drive as well. What gear ratio do you have now?
     
  4. BranndonC

    BranndonC 3/4 ton status

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    he's got a 90 k5 which prolly means 700R4 and np241 which i would go with 4.56.... i ran that tranny and t-case with 3.73's and couldn't wait to get lower gears
     
  5. sdavid

    sdavid 1/2 ton status

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    They say that is the "ideal" gear for 35s and autos with overdrive. It would definately have more get up and go than your stock gear ratio, and I'm sure you would not regret going up to 4.56s.
     
  6. zakk

    zakk 1/2 ton status

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    Your 1990 K5 has a 700R tranny in it, which means you can reap the benifit that OD gives you.

    For free, a set of 4.56's is hard to beat. A few people he have that exact set-up and are going higher. 5.13's are the hot set-up for 700R tranny's as it gives them more of a mechanical advantage over the tires (espaically when you go to a larger tire), and still will keep RPM's at a reasonable level.

    but if you are 1/2 the pinions will be getting acorn sized, so 4.56 may be wise, and just deal with the lack of performance.
     
  7. BranndonC

    BranndonC 3/4 ton status

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    /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif before i even read this the first time i though "I bet zakk will reply something having to do with 5.13's" you know... knowing it's a gear post and all.

    dont get me wrong, i'm the same way now, i loved my 5.13's for the 100 miles i got on them before my truck became undriveable, but i whole heartedly agree 5.13's are the way to go
     
  8. zakk

    zakk 1/2 ton status

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    [ QUOTE ]
    Zakk’s Dissertation on why 5.13’s are the best choice for a 700R

    Recently, I made the switch to 5.13’s in my D60/14B combo. I run a mildly build TH350 and 39.5” TSL’s. The 4.10’s I did have were killing everything: the motor, the trans, freeway “ get up” …all of it was terrible.

    So, after typing this up a few times, I will commit this document to the annals of time, and have a friend of mine host it.

    The problem with larger tires and a 700R and larger tires, is that you can’t seem to get enough RPM’s to get the OD to properly engage.

    Dr. Watson of ORD fame has this problem with the Art Carr 700R and his 42’s. There is just not enough RPM’s to shift in OD. So what little freeway driving he does do, is all done in Drive.

    When we mix this with tires in the 35-38” range, 5.13’s are a great choice.

    Assuming a true tire dimension of 35”, a vehicle with a small block motor mated to a 700R would spin 2241 RPM’s. Running with 4.88’s would have the engine humming along at 2132 RPM’s, only saving 109 revolutions of the motor per minute. All are calculated at 65 MPH.

    Assuming a true tire size of 37”, 5.13’s would net 2120 RPM’s at 65 MPH.

    Most small block motors are comfortable running between 1800 and 2800 RPM’s. 5.13’s with the addition of OD allow this number to be on the lower end of the spectrum, while allowing for maximum acceleration and off road performance. Gearing can make a motor that is slightly lighter on power really come alive, as I have found with my mild small block 350 with approximately 285HP at the flywheel.

    In closing, unless you bought your axles with 4.88’s already installed, there is no reason that this author sees to not go with 5.13’s from your present gear ratio.

    Let the flaming begin….


    [/ QUOTE ]


    you mean that? /forums/images/graemlins/grin.gif

    what happened to your rig? i thought it was all done? /forums/images/graemlins/confused.gif
     
  9. BranndonC

    BranndonC 3/4 ton status

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    all done? lol my rig will never be "all done"
    Anyway on July 10th i picked up the truck from jason and drove it home. about 100 miles into the trip my t-case siezed up and i threw my new high-angle cv shaft on the freeway doing 70. so i got it towed home, bought a new t-case from rocko, resealed it, painted it, installing it today, still have to ship out my shaft for repair. I took out my 6 inch blocks and am recieving 4 inch blocks from sapper tomorrow, removed some leafs from the front springs and now i just gotta put it back together /forums/images/graemlins/smile.gif

    The good part about this is i got an air compressor. 6Hp 33 gal.

    And i'd like to let everyone know what a great guy BobK is. He's came over every day he can to help me with most of this and taught me more about my truck that i didn't know.
    [​IMG] [​IMG] [​IMG] /forums/images/graemlins/thumb.gif
     
  10. Confedneck

    Confedneck 3/4 ton status

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    thats a purty t-case you got there...
     
  11. SUBFAN

    SUBFAN 1/2 ton status

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    Seized your T-Case? any ideas as to why?
     
  12. BranndonC

    BranndonC 3/4 ton status

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    yes... no fluid for a long time nad it was already damaged from a previous breakdown /forums/images/graemlins/shocked.gif /forums/images/graemlins/rotfl.gif
     

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