Rear Factory Locked Axle Shaft Mod

RockJock82

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I wanted to share some knowledge that I acquired from a friend regarding modifying your rear passanger side axle shaft. This will allow you to remove the twisted portion of the axle shaft if it breaks under load. My friend Kenny documented the process and dimensions where to modify the shaft. This can be done in your garage with an angle grinder or taken to a shop with a lathe. Lucky for him he has both :).
 

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RockJock82

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Would you think the mod would make the shaft weaker? I don't believe it would as you are just removing the splined portion that binds. This is the same exact mod LandTank does to the shaft
 

LandCruiserPhil

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Would you think the mod would make the shaft weaker? I don't believe it would as you are just removing the splined portion that binds. This is the same exact mod LandTank does to the shaft
Kennys mod is similar to LT but not exact. As for strength I have no idea. Is one stronger or equal to the other is a good question? Hopefully someone with an educated background will chime in. Does Kennys mod have any breaks without removal issues?
 

RockJock82

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Your removing splines off the shaft that ride in dead space i. the carrier. I can't see how that would effect if any the integrity of the shaft. But again I'm not an engineer, though Kenny is :). I'll PM him and have him chime in.
 
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The only way I can see it causing a problem is when grinding or in the lathe getting the shaft to hot in one spot causing it to be weak and braking at the hot spot or if you do it by hand and cut just a little to far into the shaft
 

RockJock82

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Yes that is a possibility. There's always the option like I mentioned above to take it to a machine shop as well. I will just machine my own
 
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I'm a machinist, and have run my own machine shop/auto repair shop for years, i can tell you what he has done here will not weaken that shaft. All he is doing is taking the splines on the shaft down to the minor diameter of the splines. Seeing as those splines are harden, the only thing i would have done different, would have been to use a tool post grinder with coolant. Using coolant would protect the heat treat of the splines next to where he's grinding. Plus using a tool post grinder will give you a uniform depth of grind, unlike using a hand held grinder, and you can put a radius on both sides of the grinding wheel, that way you prevent creating a stress riser.
 
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Im planning to do this soon. However to be honest i am considering machining a groove, approx like an o-ring dimension groove at the outboard end of the shaft approx .020" or so as an intended weak spot. With the intent being that it hopeful y breaks leaving a nice easily accessible length of shaft. I don't quite moab so I should be fine in my neck of the woods 99% of the time.
 
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Assuming that Land Tank is no longer machining these axles and we are on our own, what is the proper dimensions/drawing?
If you look in both the first, and second thread above there are links to a downloadable file that has the dimensions your looking for.

Im planning to do this soon. However to be honest i am considering machining a groove, approx like an o-ring dimension groove at the outboard end of the shaft approx .020" or so as an intended weak spot. With the intent being that it hopeful y breaks leaving a nice easily accessible length of shaft. I don't quite moab so I should be fine in my neck of the woods 99% of the time.
If you follow the blueprints listed in the above downloadable files, they both list the correct dimensions to machine your axles. If you machine your axles per those prints, you'll be able to remove them if you twist the splines, so there really is no good reason to machine a "intended weak spot" in your axle. Just my 2 cents YMMV.
 
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If you look in both the first, and second thread above there are links to a downloadable file that has the dimensions your looking for.



If you follow the blueprints listed in the above downloadable files, they both list the correct dimensions to machine your axles. If you machine your axles per those prints, you'll be able to remove them if you twist the splines, so there really is no good reason to machine a "intended weak spot" in your axle. Just my 2 cents YMMV.
So both files are different from each other but they are both correct? Which one is better?
 
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The point of the mod I understand. The reason I made my suggestion was just based on wanting the axle to break in an ideal spot when in the woods. I realize its not ideal, however it would be nice to know that when you do get a breakage, the majority of the shaft is intact for easier removal. Rather than having to pull the third to extract a small piece or having to use magnets etc.
 

landtank

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I received a report that one of my shafts broke. It broke at the edge of the splines where the machining started. So you could pull out the majority of the shaft but the remainder was still in the diff.
 
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That's exactly what I don't like. Having full float should make things easier in many cases. But when you still have to pull the third in the woods.....
 
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I received a report that one of my shafts broke. It broke at the edge of the splines where the machining started. So you could pull out the majority of the shaft but the remainder was still in the diff.
When you machined the axle shaft did you incorporate a generous fillet radius into each corner of your cut?
 
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