Payload vs Upgrades -- a cautionary tale

[Headbarcode]

My FAD Failed this weekend. I off-road about 2 times per month... So I am thinking of Deleting the FAD, and go with RCV Axle Shafts to do so.

https://www.rcvperformance.com/ulti...set-for-jeep-wrangler-jl-rubicon-1-piece.html

I know the Front Driveshaft will now spin, and that may or may not be problematic... So I am not sure on the Plan of action at this moment.

This is the Broken Piece I found when I removed the FAD.

It isn't the c-clip... seems like Plastic?

My FAD failed and the dealer replaced the drive train control module and the switch at the FAD. Works correctly now. I plan to do the FAD delete and add the truss. I hope the axles are good enough to avoid the RCV cost.

Just a friendly heads up. As CarbonSteel mentioned a couple pages back, a FAD delete on a factory axle may result in vibrations at highway speeds. I say "may" rather than "will", because it depends on where your caster is set. If at factory specs, which tend to be too low in actuality, than it should be fine. If caster has been set to the 6-6.5° happy range, the pinion will be at too much of a down angle in relation to the driveshaft, because Dana welded the inner C's to Jeeps caster specs. This will be amplified in relation to any lifted ride heights.

For those of us that increased caster to correct steering feel, having the FAD in play keeps those vibrations away. And if road conditions become bad enough to require 4hi, it's nothing shy of foolish to still be driving at those higher vibration inducing speeds anyway.

That's why I opted for the 2-piece RCV's on my JLUR. They are twice as strong as the oem Rubicon Dana 44 shafts, and stronger than Dana 60 ujoint shafts. The 1-piece version is only marginally stronger than the 2-piece.

The FAD weakness is due to the window in the axle tube, rather than in the shafts themselves. Strengthening the tube, while retaining the FAD, will fruit the most benefits.

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[Zandcwhite]

Just a friendly heads up. As CarbonSteel mentioned a couple pages back, a FAD delete on a factory axle may result in vibrations at highway speeds. I say "may" rather than "will", because it depends on where your caster is set. If at factory specs, which tend to be too low in actuality, than it should be fine. If caster has been set to the 6-6.5° happy range, the pinion will be at too much of a down angle in relation to the driveshaft, because Dana welded the inner C's to Jeeps caster specs. This will be amplified in relation to any lifted ride heights.

For those of us that increased caster to correct steering feel, having the FAD in play keeps those vibrations away. And if road conditions become bad enough to require 4hi, it's nothing shy of foolish to still be driving at those higher vibration inducing speeds anyway.

That's why I opted for the 2-piece RCV's on my JLUR. They are twice as strong as the oem Rubicon Dana 44 shafts, and stronger than Dana 60 ujoint shafts. The 1-piece version is only marginally stronger than the 2-piece.

The FAD weakness is due to the window in the axle tube, rather than in the shafts themselves. Strengthening the tube, while retaining the FAD, will fruit the most benefits.

I think the potential vibrations are over played. I have run 7⁰ to 8⁰ of caster in both JLs we've owned, both on 3.5" of lift, and never felt any vibrations in 4HI. Unlike most, we run wide open desert trails at freeway speed. Sometimes in 2wd and sometimes in 4hi. We were hitting 50+ yesterday in 5ft deep snow. I think you'd have to be running 6+" of lift or double digit caster for it to be a problem in a JLU in my experience.

 

[Headbarcode]

I think the potential vibrations are over played. I have run 7⁰ to 8⁰ of caster in both JLs we've owned, both on 3.5" of lift, and never felt any vibrations in 4HI. Unlike most, we run wide open desert trails at freeway speed. Sometimes in 2wd and sometimes in 4hi. We were hitting 50+ yesterday in 5ft deep snow. I think you'd have to be running 6+" of lift or double digit caster for it to be a problem in a JLU in my experience.

You know the deal. There's so many factors involved, that what works for some Jeeps doesn't work for others. About 6.5-7° caster is my sweet spot, sitting 5.5" above stock height in the front and 6" in the rear. I tried getting greedy by chasing up on 8°, but it caused a drop in the ride and handling quality with my specific Jeep and setup.

I just simply wanted to help others to avoid dropping a decent amount of cash on a set of 1-piece RCV's, that are only marginally stronger than the 2-piece version, just to possibly end up with a vibration. On top of that, the real FAD weakness (window punched in the axle tube) will still be in play.

The safest money would be the 2-piece RCV's, which are stronger than Dana 60's, and a strengthened factory axle tube. I'd personally rather avoid any possible negative side effects, just to gain a marginal further increase in axle shaft strength.

 

[DonBucket]

Just a friendly heads up. As CarbonSteel mentioned a couple pages back, a FAD delete on a factory axle may result in vibrations at highway speeds. I say "may" rather than "will", because it depends on where your caster is set. If at factory specs, which tend to be too low in actuality, than it should be fine. If caster has been set to the 6-6.5° happy range, the pinion will be at too much of a down angle in relation to the driveshaft, because Dana welded the inner C's to Jeeps caster specs. This will be amplified in relation to any lifted ride heights.

For those of us that increased caster to correct steering feel, having the FAD in play keeps those vibrations away. And if road conditions become bad enough to require 4hi, it's nothing shy of foolish to still be driving at those higher vibration inducing speeds anyway.

That's why I opted for the 2-piece RCV's on my JLUR. They are twice as strong as the oem Rubicon Dana 44 shafts, and stronger than Dana 60 ujoint shafts. The 1-piece version is only marginally stronger than the 2-piece.

The FAD weakness is due to the window in the axle tube, rather than in the shafts themselves. Strengthening the tube, while retaining the FAD, will fruit the most benefits.

Thank you. I called RCV as well, and they claimed the have not had a 2-piece axle fail, but get multiple guys calling back after the 1-piece having an issue with vibration.

Because I still drive to the trail (2 Hours Highway) I am going to Keep the FAD and get the 2-Piece RCV.

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