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Unread 07-17-2014, 12:50 AM   #1
blaserman33
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Axle Shaft Strength Question

I am not trying to bring up ye 'ole HP D30 vs LP44 v Rubi 44 strength debate. I am looking at just the strength of the axle SHAFTS, not overall axle strength. So my question is would Chromo D30 shafts be stronger than stock Ford Dana 44 shafts? I know they both use the same u-joint, so I guess it mostly comes down to whether the Higher Grade Alloy would beat out the stock D44 shafts larger diameter?

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Unread 07-17-2014, 01:08 AM   #2
aagill225
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Spline count at a major part too. I think the d30has a 27 spline count and the 44 is 32 (maybe) I'm sure it's here In he spec section. The more splines will give a stronger hold.
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Unread 07-17-2014, 04:27 AM   #3
rda616
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Quote:
Originally Posted by aagill225
Spline count at a major part too. I think the d30has a 27 spline count and the 44 is 32 (maybe) I'm sure it's here In he spec section. The more splines will give a stronger hold.
A ford dana 44 has 30 spline shafts. The ears on the stock dana 44 shaft will fail before the chromoly dana 30 shaft will break. In stock form both axle shafts are most likely to break at the shaft ears since there is no more material on one vs the other.
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Unread 07-17-2014, 06:11 AM   #4
blaserman33
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Quote:
Originally Posted by rda616
A ford dana 44 has 30 spline shafts. The ears on the stock dana 44 shaft will fail before the chromoly dana 30 shaft will break. In stock form both axle shafts are most likely to break at the shaft ears since there is no more material on one vs the other.
So since the yoke ears are the most common fail point and the ears are the same on both then wouldn't they both be about the same strength even in Chromoly? But since the D44 has stronger tubes, knuckles, larger diameter shafts, etc. the axle in General is a lot stronger even if the shafts aren't that much stronger, is that correct?
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Unread 07-17-2014, 07:55 AM   #5
mrblaine
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Originally Posted by aagill225 View Post
Spline count at a major part too. I think the d30has a 27 spline count and the 44 is 32 (maybe) I'm sure it's here In he spec section. The more splines will give a stronger hold.
In general, not really. The reason that spline count gets confused is larger axles have more splines by virtue of splines generally being the same size so there are more of them on larger diameter axles.

To clear up your confusion, see how many instances of stripped splines you can find.
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Unread 07-17-2014, 08:22 AM   #6
rda616
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The advantage I see with a dana 44 is a wider range of gear choices. The ball joints and u-joint are the same. The axle tubes are thicker on a ford dana 44 and the case will likely have a bit less deflection, but the question should be does it matter for what you do. A hp30 is plenty strong for up to a 35" tire, weighs less, and has better ground clearance.
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Unread 07-17-2014, 08:46 AM   #7
RWKHausSupply
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Originally Posted by rda616 View Post
The advantage I see with a dana 44 is a wider range of gear choices. The ball joints and u-joint are the same. The axle tubes are thicker on a ford dana 44 and the case will likely have a bit less deflection, but the question should be does it matter for what you do. A hp30 is plenty strong for up to a 35" tire, weighs less, and has better ground clearance.
Ball joints are different on Ford D44 and HPD30.
Ujoints are the same (as long as the larger 297/760).

Look in to Revolution Gear & Axle soon for LP/HPD30 shafts that use the Much larger JKD44 front ujoints, and I would assume the ears being wider apart allow for more forces before breaking. Same OD shafts though at the seal surface and splines, and same outer stub dimensions.
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Unread 07-17-2014, 09:04 AM   #8
rda616
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Originally Posted by RWKHausSupply
Ball joints are different on Ford D44 and HPD30.
My bad I was thinking rubi 44 for a second.
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