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Dana 70 or 14 Bolt FF?

Discussion in 'The Garage' started by afroman006, Jan 11, 2003.

  1. afroman006

    afroman006 1/2 ton status

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    Is a dana 70 or 14 bolt FF better? I know their ring gears are almost exactly the same size but are there other little things that makes one superior? I have looked around and found out that a Detroit locker for the dana 70 is $220 more than for a 14 bolt /forums/images/graemlins/eek.gif. What I am interested in is a dually axle. I know there are plenty of dually dana 70's out there and am prety sure sure there is a fair number of 14 bolt duallies too. Which would be better? Thx
     
  2. TX Mudder

    TX Mudder 1/2 ton status

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    The Dana 70 and 14 bolt are about equal. I like the 14 bolt because it uses the extra pinion bearing - I don't think the Dana 70 has this.
    The REAL reason why the 14 bolt is better, however, is because of the $300 detroit locker. The 14 bolt carrier is big and beefy so instead of making a carrier replacement, they just made it a drop-in. Cheap and no need to reset the gears.
    Plenty of duallys, but you'll need to move the perches if you don't have a 1-ton frame.
    -- Mike
     
  3. u2slow

    u2slow 1/2 ton status

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    A Dana 70 DRW is 73" while most 14-bolt DRWs are from cab& chassis models an measure only 62". A 73"-range 14-bolt had to be from a 92-up DRW *pickup*.

    A 1-ton DRW cutaway van is 73" as well. D70 up to '91. 14-bolt from 92-onward.

    Perches will probably need to be moved in most cases.
     
  4. m j

    m j 1/2 ton status

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    the 14ff benefits are mostly in the areas of set up ease etc.
    70 has the advantage of being still in mass production and parts are available from all big 3 dealerships as well as a billion dana distributors.

    super deep ratios are available for the 70 but IMO deep reduction is best done up in the gearboxes thanks to ORD and others so no real plus there
     
  5. tarussell

    tarussell 1/2 ton status

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    Since you are looking at "dually" rear ends you may want to consider the GM version of the HD 70 .
    The 14 bolt and the "B" series 70's are very similar in strength and size, but the HD 70 is a different story.
    It has a HUGE inner pinion bearing and very large carrier bearings - along with larger wheel hub bearings.The HD version also has 4" dia. axle tubes w/ 5/8 thick walls.
    This axle was intended to carry some serious weight !

    The D/L is more exspensive than the 14 bolt but if you get lucky and find an open diff. HD 70 that has a two piece case ( not the one piece case ) and just get the inards of the D/L just like the 14 bolt ( Dana 70 D/L's use the older {no longer made} two piece open diff. case for the D/L's )it should save you some dollars.
    The 14 bolt is a GREAT axle , but the HD version of the 70 is a real heavy hitter in the weight capacity dept.
    Just my $.02 worth , Tom
     
  6. 72THING

    72THING 1/2 ton status

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    I agree that a 14FF and D70 are comparable in strength, but the cheapness of a Detroit for the 14FF makes me lean in that direction. Here's something else to consider; my friend had a D70 HD from a F-350 cab & chassis dually and he kept breaking axleshafts in it. He had 44s with just a mild 355 SBC. He has since gotten a 14FF and has yet to break an axle, even though the 14FF shafts neck down before the splines and the D70 shafts are about the same diameter from end to end. I'm not an engineer, so I wouldn't know why the D70 shafts broke and the 14FF shafts are holding up just fine. It baffles me. /forums/images/graemlins/confused.gif

    Will
     
  7. ZonkRat

    ZonkRat 1/2 ton status

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    If the brand of truck isn't a problem check or the Ford {sterling}10.25. I scored a DW with 4,10s and open diff. for 125$ cause most around here are D60 crazy.It also has 1.5 inch 35 spline axles.It has more ground clearance than a shaved 14 FF and nice big windows for a lincon locker.Not sure bout width,but,It tracks just right with the D60 up front. /forums/images/graemlins/crazy.gif /forums/images/graemlins/truck.gifer on 38s /forums/images/graemlins/thumb.gif
     
  8. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    Dana 70 has bigger, thicker axle tubes and more ground clearance than a 14 FF. Plus, gearing can go lower than the 14 bolt. 14 bolt shafts are 1.5" 30 spline, Dana 70 (older) are 1.5" 19 spline and (newer) 1.5 35 spline. Ring gear in the D70 is 10.54"
     
  9. Sandman

    Sandman 3/4 ton status Author

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    Now theres a good idea. /forums/images/graemlins/grin.gif
     
  10. DEMON44

    DEMON44 Low-Tech Redneck

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    ...but you can get at least a 5.86:1 gear for a 14FF. Any more than that is getting retarded low. Unless your running over 44" tires.
     
  11. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> Lowest gear I've found for a 14b FF is 5.13s. Where did you find the 5.86s? </font color>
     
  12. DEMON44

    DEMON44 Low-Tech Redneck

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    <font color="red">ERROR-MY BAD! </font color> It's a D70 I was thinking about, A guy is selling a D60/D70 combo, I thought it was a 14FF. They're here in Calgary though.
     
  13. u2slow

    u2slow 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    along with larger wheel hub bearings

    [/ QUOTE ]

    Where can I get more info on this? The hubs and drums are identical on a Dana 70 DRW and 14-bolt DRW.

    Only times I've found larger hub bearings are with 10-lug versions of the Dana 70, Dana 80, and Rockwell.
     
  14. tarussell

    tarussell 1/2 ton status

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    U2SLOW - I was thinking that I remembered that the HD's in the C/K3500's had a different inner wheel bearing, but I may have had a case of memory fade. I am certain that the outer bearing is the same-as you pointed out.

    According to an old BCA bearing book the bearings should be 387AS-382A for the inner and set A-38 for the outers for both the 14 bolt FF and the HD 70's- just like you mentioned. The Rockwells and Dana 80's of that era had KD-12051-Z for the inners and the 387A-382 for the outers . For some reason I thought that I recalled the HD's using a larger inner bearing......
    I have an old HD 70 hub with the bearings still in it in the garage, so I will break it down tomorrow to confirm what is in it.
    According to the bearing refferance books they do have the same bearings, so I may very well have spoke out of turn with some miss leading info on the wheel bearings. Now I need to recall what axle housing had the bearings that I was thinking about?????
     
  15. u2slow

    u2slow 1/2 ton status

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    You are right about the 4" axle tube /forums/images/graemlins/wink.gif

    I didn't think they could fit any bigger bearings inside the 8-on-6.5" bolt pattern.

    This is one of the 10-lug Dana 70's with the bigger hub bearings. Its from an GM-based A-class motorhome.
    [​IMG]
     
  16. tarussell

    tarussell 1/2 ton status

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    Man-O-man , I was wrong about the inner bearings for sure !
    They are the 387's like the 14 bolt stuff.I guess I my brain fade is stronger than I realized.....
    Question - You said that the hubs and drums are the same part #'s - So I can interchange the HD 70 hubs and the 10.5 hubs??? The reason that I ask is that I have access to a few 10.5 Chassis Cab Dually rear housings and I could use the spare hubs for the HD 70's.I never looked at the bearing position in the hubs because I was still thinking that the bearings were different---Another good reason to double check things instead of assuming.

    I came across a HD 70 ( motorhome chassis )like your 10 lug version but it had a huge six lug pattern and the big bearings.It had calipers similar to the GM big single piston sliding design.

    Would it be possible to take a GM 10.5 Dually hub and put it on a SRW 10.5 housing ? Ex: If you had a 10.5 out of a SRW P-series Service Van that was wide and you wanted the track width closer to a C/K 10.5 - could you put some Dually hubs on it to bring in the wheel mounting flange. I realize that the brakes are an issue but would the bearing spacing remain the same(inner to outer)?

    Thanks for the info and sorry for the wrong info on the inner bearing ...... Tom
     
  17. u2slow

    u2slow 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    Would it be possible to take a GM 10.5 Dually hub and put it on a SRW 10.5 housing ?

    [/ QUOTE ]

    Yup. Guys with Jeeps do this with C/K SRW's to bring the track width down a little. You have to engineer your own brakes though /forums/images/graemlins/wink.gif
     

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