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4.56 or 4.88 with a 700r4

Discussion in 'The Garage' started by muddawg, Mar 24, 2005.

  1. muddawg

    muddawg Registered Member

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    Which gears would work best for my 700r4 with a strong 454 and 3/4 ton axles with 37x14.5 tires? 4.56 or 4.88's? I have a b&m 24000 stacked plate cooler,temp gauge, and the tranny has been somewhat beefed up. I want to try to keep my rpm's down on the highway for mileage but don't want to burn up my trans or have it hunting for gears.
     
  2. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    why do I think someone is gonna say 5.13's?????

    anyhow...
    with auto.. depends if you are gonna make a trail rig trailered or driven...
    id say 4.56's if gonna see highway alot...

    im probably going 454 this summer.. gonna keep my 4.56's :cool1:
     
  3. crazy427

    crazy427 1/2 ton status

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    Took the Word out of my mouth.....5.13ssss are the only way to go.


    im running a tbi383,700r4 ,14bff w/posi,frt 10 bolt lockedand 37x12.5x16.5 swamper radials.....awsome take off, awsome off road and i cruise at 80 mph with the enigine rpms at 3000 and 2800with the converter locked.



    :cool1:
     
  4. 6.2Blazer

    6.2Blazer 1/2 ton status

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    There's not that much of a difference between 4.56 and 4.88, but with that said I would go with the 4.88.

    Rootbreaker - keep in mind that 4.56's with a 700r4 tranny is a LOT different on the highway than your truck with 4.56's and the SM465 tranny. The 700r4 in OD on the freeway would be equivalent to 3.20 gears (4.56 x .70 OD ratio).
     
  5. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    I figured that... :grin:
    I am contemplating a nv4500 tranny... once I go there we will see if i change axles.. may even go mog or rockwells.. dunno yet.. I also want 4 wheel steering...:cool1:
     
  6. muddawg

    muddawg Registered Member

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    It is my daily driver so it probably sees about 80% of its time around town and on highway.
     
  7. 7blazer5

    7blazer5 Registered Member

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    I know this isn't my post but can someone tell me what would be the best gears for my 75 K5. I am running 35" tsl's on a 6" lift but still have stock gears. I was planing to either keep these tires or maybe go with 36's.
     
  8. crazy427

    crazy427 1/2 ton status

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    Gears for each person is goin to be different. It all Depends on the power band of your engine,Which transmission and the tire size.Then after that you still have a few choices depending on what % of Off-road to street time your truck see's. If your 75 is a trail only truck and doesnt have overdrive i would say 4.56, If it see's the trails only once in a while and spends alot of time on the street i would say 4.10. Now if your running a overdrive i think that any tire 36" or over should be running a 5.13. Not just for take off and cruising speed but for the fact that the 700r4 's Build up alot of heat easily so you want the least amount of strain put on it. By using the taller gear you are Eleviating alot of strain and the Highway cruising speed with a 700r4+5.13 and 36" 37"or38" tires usually puts the engine in the right cruising rpm range so the converter isnt strugling and creating extra heat.
     
  9. Jonny-K5

    Jonny-K5 1/2 ton status

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    with a 700 you want at least 4.88. i'd go 5.13, tho thats pretty steep for the front 10b. my truck has 4.56 w/ lil 33's and a 700, i think its perfect. i can cruise all day at 80mph, turning about 2800rpm. if your converter is locking up correctly the rpm's drop. usually by about 200.

    7blazer5, depends on how much freeway driving you do, how fast you like to go on the freeway, and how much you go offroad. if you do alot of offroading, then probly 4.56,maybe higher. mostly onroad, i'd go with 4.10. like to drive in the fast lane? no more than 3.73. its a compromise when you dont have OD. you can go to www.4lo.com , they have a calculator to find out what your rpms will be with your gear/tire combo at freeway speeds.

    where do u live in SA? i live over by the DMV on 1st St
     
  10. 7blazer5

    7blazer5 Registered Member

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    I live right by the intersection of Bristol and Segerstrom but I am always around that area by where you live at cause I always hit up MOS 2
     
  11. Jonny-K5

    Jonny-K5 1/2 ton status

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    whats MOS 2?
     
  12. 7blazer5

    7blazer5 Registered Member

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    WHAT?????:confused:

    You live in SA and don't know about MOS. Thats the little ghetto fast food place right next to the DMV it looks like it used to be a Taco Bell. Try it out, that place is really good. Do you atleast know who Cheerio is? Every one in SA knows who he is.:D
     
  13. blackblazer717

    blackblazer717 1/2 ton status

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    i say for a DD i would go 4:56's only because it sees alot of street and the R's wont be huge on the freeway like a 4:88 or 5:13

    LUKE
     
  14. 7blazer5

    7blazer5 Registered Member

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    I want to be able to drive it to the dunes, go wheeling and be able to drive it back instead of towing it there
     
  15. 85mudblazin

    85mudblazin 1/2 ton status

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    I got 4.88's with 35's and I wish I went with 5.13's, if you ever plan to go to a different tranny say a TH400 then you will need big tires to keep the RPM's in check.
     
  16. 7blazer5

    7blazer5 Registered Member

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    Will 5.13's be the best way to go with the set-up that I have?( 350 w/3-speed manual on 35's)
     
  17. 85mudblazin

    85mudblazin 1/2 ton status

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    Not sure with the manual tranny. But in 3rd gear(not OD) in my 700r4 There is no way you could go 65+, the RPM's are just to high
     
  18. Hossbaby50

    Hossbaby50 3/4 ton status

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    I would go with a minimum of 4.88's. 4.56's shouldn't even be an option. I would think seriously about 5.13's.

    I run 35" MTR's (33.5" actual height) with 4.56's, 700R4, and TPI injected 350. With my combo I feel that 4.56's are marginally ok, but wish I had 4.88's with my 35's.

    Harley
     
  19. HarryH3

    HarryH3 1 ton status Author

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    The engine is the key. A small block will cruise nicely in the 2500-3000 RPM range. But a big block makes a bunch of torque at low RPM. A stock 454 has a torque peak right around 1,600 RPM. Talk with the folks that made your cam and find out where the torque peak will be with the mods. Set it up so that the highway RPM will be close to the torque peak.
     
  20. muddawg

    muddawg Registered Member

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    i'm not so much worried about the power, i'm more worried about burning up the tranny by running in OD at low rpm. I have plenty of torque to pull OD at low rpms. I heard that anything under 1800 rpm in OD will create a lot of heat, thats why i'm worried.
     

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