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Dana 70 Rear Axle Tech By Bill "BillaVista" Ansell |
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IntroductionAh yes.....finally time for a real axle. I guess the hundreds of hours I spend on this website helping folks for nothin' really does pay off in karma. Because, unbelievably...I found a FFD70 rear end abandoned and rusting in the woods, and just begging to be salvaged. Who am I to refuse? Besides, I always pick up all the trash I see......it's good for the environment! |
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Clearly it had been there for some time, and nobody was planning on coming back for it. The earth had completely filled in around the wheels, over 8" deep! |
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Here it is rescued and at home. It measures 65" wms to wms. Note how it completely dwarfs my FFD60 rear from my old '79 F250. |
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Huge drums and big meaty full-float hubs! |
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10.5" dia. ring gear and 4.56
(41/9) gears. |
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And a 2-piece open carrier that is very large and strong. Reader tarussell writes: "The model 70 used a few different open carriers - some one-piece (like a Dana 60) and some two-piece (similar to a P/L). The P/L has angled ramps at the cross pin in each side of the case halves; has the innards of the L/S spiders & clutches and centring rings, and the bolts that hold the case halves together are at the end of the case instead at the low point of the casting crown like the open carrier. |
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There are some numbers cast into the
webs, but none appear to be BOM numbers. Clockwise from the driver's
top web, the numbers are: 1868818 030783 70 2018188 |
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The ring gear has some little chips, but they don't appear to be critical, and I may well trim them off if I shave the diff enough to require taking a little off the ring gear. |
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The Shafts are 35.5" long, 1.5"
dia., 23-spline, equal lengths.
They may not be 35-spline, but look how they dwarf the FFD60 30-spline axle on the right. |
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The D70 shaft is much beefier at the flange end too, D60 on the left. |
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Overall the 23-spline 1.5" shafts appear much bigger and stronger than the common 30-spline D60 shafts. |
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The tubes themselves are monstrous. They measure at 3.562" dia.!! |
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They do a little taper at the end though. This differs from my D60 tubes which are smaller, but do not taper at all. |
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Centre of the tube to bottom of uncut diff measures about 6.5", about .5 to .75" more than a 60. I will likely shave it dramatically. |
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I don't yet know what size that nut is, but freakin' huge is a good start. This side had studs for the axle flange, the other side had bolts...and 3 different sizes at that (I hoped at least all the threads were the same, and just the heads were different!) |
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For giggles, I slid in a D60 shaft, and interestingly... |
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...the axle flange bolt pattern is exactly the same. |
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D60 on the left, D70 on the right. |
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D60 on the bottom, D70 on the top. |
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D60 spindle ID 1.407". |
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D60 spindle OD 1.984" - SAME AS D70 spindle! |
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D70 Spindle OD 1.957".
I guess boring out your D60 spindles for 1.5" shafts is no big deal, as it appears the stock D70 spindle is thinner wall than the stock D60. |
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D70 spindle ID 1.630". |
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