1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

77 1/2 ton to a 1 ton

Discussion in 'Chevy Trucks' started by 77sub, Jun 2, 2003.

  1. 77sub

    77sub Junior Member
    from md
    Messages: 2

    hello all, i got a question that i am sure some of you know the answer to. i have a 77 1/2 ton suburban, right now it has a 6" lift and 35" i use it for playing around and 4 wheeling. now i want bigger tires like 44" so i want one ton axles i guess i want dana 60 no need for the 70 or is a corp 14 bolt good enough for the rear?. what do i have to do to get them under the truck i also only have blocks in the rear so i want to get new springs, was going to put 8" in the rear to make it more level with the front, but do i get ones for a 1/2 ton or a 1 ton. i also want to run lockers front and rear any help there would be good too. any clue on gears and such and i have a 350 engine with some work and a new 350 turbo trans.
    thanks for your input any would be great
     
  2. wyldman

    wyldman Member
    Messages: 3,265

    Welcome to Plowsite :waving:

    The Dana 60 front,and 14 bolt rear (get a full floater),will bolt right in.The driveshaft yokes are different,so get two 1 ton driveshafts while your at,as well as the correct corresponding yokes on the transfer case.The bigger shafts use much bigger and stronger joints.

    Springs should be matched to the weight of the truck.Go with a softride spring,as it will ride much better,unless you really need the load carrying capabilty.The stiffer 1 ton springs will beat you to death.

    Go with a Detroit locker in the rear,and an ARB in the front.You don't want a full time locker,or posi in the front,or it will never turn.The ARB gives you the ability to only lock it when you need it,so it will turn and be less likely to break something in the front axle.

    Since you don't have an overdrive trans,you won't want to go with to steep a gear,or it will kill your on road drivability and gas mileage.A 4.11 would work well if you need to do a lot of highway driving,but still have decent bottom end,or a 4.56 if highway use isn't as important.

    Convertor stall speed should also be a factor in gear selection.If your convertor is real loose,or high stall,you may need to go with a slightly higher gear,to keep the RPM's down some.
     
  3. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    I agree with everything Chris said, except gear ratio. Those 44" tires are big meats, and I think you would be better off with the 4.56's or possibly even 5.10's. The way I look at it is if you are mounting 44's, you want to get the power to the ground, and don't plan on doing too much on road driving. With tire wear on pavement, it can get expensive fast. Of course now I will go find the tire diameter - gear ratio conversion chart. I know one of the off road sites has one......

    ~Chuck
     
  4. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    http://www.4lo.com/geartable.html

    According to this one, you'd want to get 5.71's to be about the same engine (RPMs) as stock @65mph (about 2800). Better gas mileage would be 5.29's.

    http://www.superlift.com/gear.htm

    According to this one, minimum 4.88's up to 5.71's.

    It's not easy to get those big meats to start turning...

    ~Chuck
     
  5. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

  6. wyldman

    wyldman Member
    Messages: 3,265

    My apologies,I misread the question.I saw the 35's you currently have on it,and that number was stuck in my mind.With the 44's,you'll definitely want more gear,like Chuck stated above.
     
  7. 77sub

    77sub Junior Member
    from md
    Messages: 2

    thanks of all of the info so quick, thats great. all of it sounds good but i have a few more clarifying questions. here we go. so those axles will fit right onto my springs no mods needed? and do you think that my brakes will be ok? or might i have some upgrading to do? and will the steering work or do i HAVE to change that right then too? as far as the adapters for the transfer case, i have the 203 all time that i have converted already to part time. those yokes can come off of a 1 ton truck and fit onto mine?

    thanks again for the help.
    p.s if anyone knows of a shop near montgomery county that is any good in working with axles (gears and such) let me know. i plan to tackle most of this my self but i was told that gears are too hard to do myself. or a place to find these axles cheep.
     
  8. wyldman

    wyldman Member
    Messages: 3,265

    The front axles will bolt right up,but the rears may need wider spring bolts if I remember correctly,it's been awhile since I swapped one.

    You will be better off if you use the brakes off the one ton axles.It takes a lot of braking power to stop those big meat from turning.You will have to grind the front calipers if you sticking with 15 inch wheels.Check www.coloradok5.com for the details on the caliper grinding.

    If your going this far,you might want to do a rear disc conversion.It is a popular mod for the 14 bolt and there are complete kits or just the brackets available,where you source your own rotors and calipers.

    The gears should be set up by a pro,with the right equipment,or they will howl and tear themselves up pretty quick.

    You can get the correct yokes for a 203 to fit the larger one ton u-joints.Get rid of the part time kit.With the truck this modified,you don't need it anyways,and all they do is burn up the rear part of the case due to lack of lube.If you can find the parts,you could also swap in an NP205.

    You don't have to do the crossover style steering now,it will still work the way it is.I would actually prefer the stock setup,with a dropped pitman arm,and a steering block.You will have virtually no bump steer.With the crossover setup,you will get a lot of bump steer,to gain a little shorter turning radius.JMHO.

    With all this stuff,you may be better off finding a parts truck which you can just swap all the parts.