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What gears do I need....

Discussion in '1982-Present GM Diesel' started by 84CUCV, Jul 8, 2003.

  1. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    I am taking the the axles from a m1008 and putting them into my k5 and I found 3/4 ton for the m1008. the 1008 is going to be a daily driver. he has redone 3.73 and a few others. I dont want the 4.10 or 4.56. At the most this truck will have 33 on it. Thanks again Mike
     
  2. edeslaur1

    edeslaur1 1/2 ton status

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    What's the question again?

    Consider 3.42s or 3.73s. Do the math for your drivetrain & speed. 6.2s torque peak is around 1800-1900, which is the most efficient.

    Good luck
     
  3. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    What gears would be good for a daily driver? thanks Mike
     
  4. azblazor

    azblazor 1/2 ton status Premium Member

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    If you aren't going to haul with it a lot you could even go with 3.08.
     
  5. edeslaur1

    edeslaur1 1/2 ton status

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    Mike, I'll help teach you the math...

    What tranny is in the truck
    What size tire do you want to use
    What TCASE is in the truck
    Are you going to use it for hardcore 4x4
    Is it a pavement truck
    Will you be towing?
    .. If so, how heavy is your trailer
     
  6. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    It has a 6.2 400/208 combo. This will never see offroad use it going to be a daily driver. I might flat tow a truck here and there that is it for towing. Thanks mike
     
  7. edeslaur1

    edeslaur1 1/2 ton status

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    Tire size!?
     
  8. edeslaur1

    edeslaur1 1/2 ton status

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    Mike,

    With 35s (34" diameter), 3.42s, at 65 you'll be doing 2200 RPM (prolly higher by about 200-300rpm since your TH400 doesn't have a TCC)

    With 33s (32" diameter), you'll want 3.08s, which will put you at 2100(again, prolly 200-300 higher depending on what kind of converter you have)

    Here's a calculator to play with. http://www.4lo.com/ (upper RH)

    Aim to get your rpms in the torque peak at the speed you drive for best mpg.

    Personally, I'd do the 3.42s w/ the 33s and 3.73s or 4.10s w/ the 35s to help around town and accel (not that a stock 6.2 is awesome).

    If you Banks it, or plan on it, aim low on the gears (308 & 342) since the Banks adds 115 foot pounds of torque.

    HTH

    Eric
     
  9. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    Stock tiers. Thanks for the help! Mike
     
  10. u2slow

    u2slow 1/2 ton status

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    3.08 isn't available for the 14FF (you did say 3/4-ton running gear, right?) 3.21 is as close as you can get.
     
  11. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    it is going to be a 3/4 ton 14sf. I was told it bolts right up. Mike
     
  12. Tybee

    Tybee 1/2 ton status

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    [ QUOTE ]
    it is going to be a 3/4 ton 14sf. I was told it bolts right up. Mike

    [/ QUOTE ]I think the spring perchs have to be moved and also shock mounts.
     
  13. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Yup, 1/2 and 3/4 tons have perch widths of 42.5" center to center...one tons (M1008) have a perch width of 40.5". You'll be doing the perch relocation twice.

    Rene
     
  14. edeslaur1

    edeslaur1 1/2 ton status

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    Are you sure? Bear in mind, I know jack about the MilSpec stuff.

    I took 75 3/4T LB Chevy axles, u-bolts and dropped them right under my K5. None of it was MilSpec tho.
     
  15. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    Are you sure? Bear in mind, I know jack about the MilSpec stuff.

    I took 75 3/4T LB Chevy axles, u-bolts and dropped them right under my K5. None of it was MilSpec tho.


    [/ QUOTE ]

    Mil spec is 1ton and 1 1/4 ton so it's different from the 3/4 ton and 1/2 ton
    Like rene said 1/2 and 3/4 ton are 42.5" and the 1 ton and mil spec 1 1/4 ton are 40.5".
    Interestingly the 1st gen blazers and 1/2 tons also are 40.5"
    /forums/images/graemlins/thumb.gif
     
  16. u2slow

    u2slow 1/2 ton status

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    [ QUOTE ]
    Like rene said 1/2 and 3/4 ton are 42.5" and the 1 ton and mil spec 1 1/4 ton are 40.5".


    [/ QUOTE ]

    Not all mil-spec 5/4 tons have that spacing. 73-76 models are a beefed 3/4-ton. Equipment includes a Dana 44 with a bolt-on truss, 350, TH350, and NP203. These have a 42.5" spacing on the rear axle, yet have the bigger 13x3.5" brakes.
     
  17. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    Thanks for the help. Still need to find a set first. thanks Mike
     
  18. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    [ QUOTE ]
    Not all mil-spec 5/4 tons have that spacing. 73-76 models are a beefed 3/4-ton.

    [/ QUOTE ]

    There were no military GM trucks from 73-76. They started in the early-mid '80's I believe. '84? /forums/images/graemlins/thinking.gif

    Also....All first gen leaf sprung trucks (67?-72) and ALL 1 ton trucks from '73-87 had perches at 40.5".
     
  19. u2slow

    u2slow 1/2 ton status

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    [ QUOTE ]
    There were no military GM trucks from 73-76. They started in the early-mid '80's I believe. '84? /forums/images/graemlins/thinking.gif


    [/ QUOTE ]

    Maybe a Canadian thing? I have a friend that's a military vehicle collector with a '76. Add hydroboost, 4.56 gears, and 9400lb GVW to the equipment list.

    Here's one of the few links I could find with some pics:
    http://members.shaw.ca/convoyclub/chevy.htm

    [ QUOTE ]
    Also....All first gen leaf sprung trucks (67?-72) and ALL 1 ton trucks from '73-87 had perches at 40.5".

    [/ QUOTE ]

    Except the leaf-sprung 2wd from 55-72 has the 42.5" spacing. Longhorn and 1-ton are always 40.5" though.
     
  20. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    [ QUOTE ]
    Like rene said 1/2 and 3/4 ton are 42.5" and the 1 ton and mil spec 1 1/4 ton are 40.5".


    [/ QUOTE ]

    Not all mil-spec 5/4 tons have that spacing. 73-76 models are a beefed 3/4-ton. Equipment includes a Dana 44 with a bolt-on truss, 350, TH350, and NP203. These have a 42.5" spacing on the rear axle, yet have the bigger 13x3.5" brakes.

    [/ QUOTE ]

    Sorry, I guess I forgot one thing, the earlier trucks were gas powered, 3/4 tons maybe but I don't think they were M1008's
    I thought we were talking about those trucks.
    Like Joe said, those started in mid 80's, could be 84 but the 6.2l diesel started in 82 so they could have started those then too.
     

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