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D60 or D70 or D80 0r 14 bolt Corp?

Discussion in 'The Garage' started by Tweetysuarus, May 31, 2002.

  1. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    So which one the these is the best all around rear axle setup for a K-5? D60,D70,D80, or the 14 bolt Corp. ?
     
  2. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Ok, here goes my stinky opinion...

    First the 60 and 80. Generally the 60's that you'll find are the smaller 1.31" / 30 spline axles. While these are great, strong axles, why (probably) spend the same amount of money and get less axle for the buck. The 80's are real beefy, most if not all, are the 1.5" / 35 spline axles with roughly an 11.5" ring gear - can't argue with the fact that they are big! But, they can be more expensive because they're newer and they are limited to a 5.38 gear ratio (this ratio is only available at a Ford dealer even though it is a Dana part!). I've never priced one but I'm sure a locker aint cheap.

    As for the 70 and 14 bolt, you really can't go wrong with either one. Whatever it takes to break one will break the other. Both have a similar ring gear size and 1.5" axles but they have different splines, the 70 is usually (not always) 35 spline and the 14 bolt is 30 spline. The 70 offers far more ratio's to choose from but a locker is much more expensive. The 14 bolt is limited to a 5.13 gear but a locker (for an open carrier) is one of the cheapest on the market.

    Chances are you wont break any of these axles unless you go to a 42" or 44" tire. If you are planning to eventually go that big, don't invest a lot of money in a small axle 60.

    It really boils down to personal preference and both current and future plans. I have a 14 bolt in my truck, I have done everything wrong to it except beat on it with a hammer - it has NEVER failed on me. I love my 14 bolt and would keep it if there was a wider variety of gear ratios for it. I now want to run more gear than is available so I am currently building a Dana 70HD (see my web site for pictures). If I had had the foresite years ago to pay attention to the ratio limitations I would have started with a 70.

    Sorry, I know this is long so in a nutshell : go with a 70 or 14 bolt for sure. If you think that, no matter what, 5.13's are as big as you will ever need then buy a 14 bolt they are very common and less expensive.
     
  3. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    Hey way kool, that was a load of gold that I really needed. thanx, Bill
     
  4. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Also, the 14FF is stronger in the pinion area.

    The D60, 70 and 80 only use 2 pinion bearings to support the pinion.

    The 14FF uses 3 bearings to support the pinion. 2 are the big main bearings and the 3rd one is the small pilot bearing which supports the little stub shaft that sticks out of the tip of the pinion gear. This little stub bearing makes a better support and will withhold a stronger load, IMO. /forums/images/icons/wink.gif
     
  5. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    Good pointer! Thanx Bill
     
  6. m j

    m j 1/2 ton status

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    have you heard of d70 having pinion related problem?
    would like to see a side by side comparo photo of 70 and 14ff pinions
     
  7. thatK30guy

    thatK30guy 1 ton status Premium Member

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    I have heard of rare cases of that happening.

    I have seen a D70 that spun the bearing races for the carrier bearings before. /forums/images/icons/shocked.gif It wore grooves into the machined surfaces on both sides of the bearing caps so deeply, the rearend was no good nor salvagable anymore.

    I have never seen a 14FF with bad carrier bearing races or caps yet. /forums/images/icons/wink.gif

    Do you have a pic of the 70 and 14 side by side? I know the 70 is probably bigger, but I'm gonna stand by the 14FF any day! /forums/images/icons/wink.gif
     
  8. m j

    m j 1/2 ton status

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    I agree the 14 is a better dif.
    just havent heard a history of d70 problems either

    the 70 looks smaller to me, could be the shape though
     
  9. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Now that I remember another case of D70 problems, I remember seeing a D70 out of a Ford where the bearing races on the pinion had spun the seats in the housing.
    The owner had tried to fix it by using JB Weld to try and seat the races to the housing, but the heat from the spinning bearings and hot oil was enough to disentegrate the JB Weld and cause it to "melt" somehow.
    That rear eventually got water into it and ruined the race surfaces and the internals, too.

    I would almost bet that if the D70 had that little pilot bearing like the 14FF, the pinion would have sat in place and not "wobbled" like the 70 did. /forums/images/icons/wink.gif
     
  10. BorregoK5

    BorregoK5 1/2 ton status

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    I just saw a 14 bolt where the carrier bearings had spun at the shop that did my rear gears. He seamed concerned over checking mine because of the large volume of this problem that he sees. I think he sees this more due to his contracts with all the airborne express vans which tend to be high mile / heavy load vehicles, and probably poor maintenance gaps. Mine was fine though, and works great with 38's and 4.56. I did however eat a mystery bearing in my D60 front on the way to the SoCalBigDawgs meeting today... both pinion bearings and carrier bearings look fine but i pulled about 8 roller bearings out of the pan - pinion tip like the 14b??? <shrugs> I'll have to pull the carrier tomorrow and see!
     

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