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Front Driveshaft Angle

gpurp

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I have a new Adams 1310 on the way to replace the front shaft in my 2-dr Sport, MC 2.5 lift, 35s, etc... Doing this so I don't have to worry about an rzeppa failure. I've got 6 degrees caster dialed in with the control arms and it drives great. Do I simply bolt up the new shaft or is the pinion angle a consideration on the front? How would you even adjust the front pinion angle without killing your caster? I've seen the rear done where the pinion was straight in line with the shaft. Can someone explain pls?
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How would you even adjust the front pinion angle without killing your caster?
You don't, that's why most aftermarket axle builders will weld on the inner C's at a different angle than OEM.

But on the bright side, if you are keeping the FAD, you don't have to worry about front pinion angle.

If you are ditching the FAD, keep the caster where it is and go for a test drive with the new driveshaft. Hit the highway and get up to your normal cruising speed. If there are no vibrations, great, you're done. If there are vibrations, you're going to have to sacrifice some of your caster to get rid of it.
 
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gpurp

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You don't, that's why most aftermarket axle builders will weld on the inner C's at a different angle than OEM.

But on the bright side, if you are keeping the FAD, you don't have to worry about front pinion angle.

If you are ditching the FAD, keep the caster where it is and go for a test drive with the new driveshaft. Hit the highway and get up to your normal cruising speed. If there are no vibrations, great, you're done. If there are vibrations, you're going to have to sacrifice some of your caster to get rid of it.
That's kinda what I thought. I'm keeping the D30 and FAD so I guess the shaft shouldn't be spinning while in 2wd. When I'm in 4wd i won't be going highway speeds.
 

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The JE Reel shafts include new front and rear axle pinion yokes. While this adds some complexity to the installation, it moves the lower front U-joint closer to the axle (even if only an inch), but this does slightly improve driveshaft angles.
 

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The JE Reel shafts include new front and rear axle pinion yokes. While this adds some complexity to the installation, it moves the lower front U-joint closer to the axle (even if only an inch), but this does slightly improve driveshaft angles.
Some complexity if you donā€™t follow proper procedures.

A lot of complexity and work if you do.
 

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Some complexity if you donā€™t follow proper procedures.

A lot of complexity and work if you do.
I replaced my driveshafts when I was regearing the axles, so there was no additional complexity or extra work to install them. This is where it's helpful to plan the build at the beginning to ensure the modifications are done efficiently.
 

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T50, 32mm, 15mm and 8mm is all you need. 6Ā° caster is of very little concern for pinion angle.

Brett
 

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Here's what it looks like installed. You can easily see the diff isn't perfectly in line with the shaft. I took it for a short test drive and couldn't feel any vibration in 4wd but didn't get over 40mph. I don't think I'll be going that fast on trails anyway.

front-ds.jpg
 

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If you didn't disable your FAD (either with an RCV one-piece axle shaft or a FAD disconnect kit, you should feel a difference.
Even if you did change your FAD operation, you still shouldn't.
 

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gpurp

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Torx Plus? I didn't know such an animal existed. I used a plain old T50 but thought it felt a little loose. More tools to buy <sigh>. I was surprised at the little 8mm 12-point bolts used for the Adams t-case yoke. All my small sockets are 6pt but luckily I had a ratcheting combo wrench.

Here's the old rzeppa CV shaft as I was getting it unbolted. The angle you see if from a 3" lift with me sitting on level ground. No wonder the CV boot fails with the higher lift kits. You don't have much room to work up in there. I haven't done anything with the FAD or axle shafts. I want to see how much mileage I can get out of this D30.

rzeppa.jpg
 

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2Wheel-Lee

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As odd as it sounds, now that I don't have my stock shafts in my Jeep, I still carry the IP45 bit in my tool bag. Maybe I might need to remove someone else's driveshaft on trail?

I've seen reference to some other bolts in the JL using either IP45 or IP50, but I don't recall where. Seat bolts? I don't know.

gpurp, it's not so much lift height that dictates the need for a new front driveshaft, it's more shock extension. Though the recommendation varies, most typically recommend a new front driveshaft with front shocks having an extended length of 28" or 29". Any more than that is what allows that stock drive shaft to drop below it's limits. The reason why lift height isn't really the factor is that there are 2.5" lifts with shock lengths in that neighborhood, and some 3.5" lifts that far exceed that extended length.
 

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Does anyone have any experience with offset ball joints? They could be used to add caster (or camber) to a straight axle.

82723510.jpg
I suggested that to a friend with JK axles trying to do the same, but he researched it and said that there weren't any companies offering more than about a degree and a half (I don't remember if it was upper or lower). I thought there would be more options.

I don't believe there are many options for JL ball joints.
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