Adams drive shaft - required?

[failsafe306]

I’ve lifted 6 JLs now. I guess I’ll call it a hunch. Have you cycled the suspension on these things?

I have not lifted 6 JLs. What do you think caused the damage in this case? I’m still assuming he’s not running more than a 28” shock with that lift. So if it’s not shocks and not ride height, what is it? Be specific so I can learn.

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[word302]

I have not lifted 6 JLs. What do you think caused the damage in this case? I’m still assuming he’s not running more than a 28” shock with that lift. So if it’s not shocks and not ride height, what is it? Be specific so I can learn.

It is impossible for the drive shaft to eat itself like that without a front shock longer than 29". With longer shocks it allows the axle to droop far enough to cause the driveshaft angles required to do that kind of damage. That's why Metalcloak always recommends replacing the drive shaft (all their shock options are longer than 29" extended) and RK recommends it when going with longer shocks.

 

[beast40]

No, it's not. Even at full droop hanging on a lift with 29" shocks the cup won't come into contact with the shaft. I'm not making this up.

You are just being suborn at this point. I'm about to bust out of MS Paint to explain why, but I shouldn't have to.

My front shocks are 28.45" fully extended, you are just regurgitating something you read.

Here is a pic of my DS at ride height while I was removing it.

 

[word302]

You are just being suborn at this point. I'm about to bust out of MS Paint to explain why, but I shouldn't have to.

Here is a pic of my DS at ride height while I was removing it.

Not being stubborn at all. What is your caster angle in this picture? With the caster set at 6+° and front shocks extended 29" or less it just simply won't hit, at least not enough to do any significant damage.

 

[beast40]

Not being stubborn at all. What is your caster angle in this picture? With the caster set at 6+° and front shocks extended 29" or less it just simply won't hit.

Right at 6. Pinion is right at 0. Going to 7-8 would make the problem worse not better.

 

[failsafe306]

With longer shocks it allows the axle to droop far enough to cause the driveshaft angles required to do that kind of damage. That's why Metalcloak always recommends replacing the drive shaft (all their shock options are longer than 29" extended) and RK recommends it when going with longer shocks.

I agree, but according to his sig, he’s running a Clayton lift, not a MC. I think that’s where our disconnect is.

 

[word302]

I agree, but according to his sig, he’s running a Clayton lift, not a MC. I think that’s where our disconnect is.

Lift manufacturer shouldn't matter here. That has nothing to do with the geometry we're talking about. I mentioned Metalcloak because the shocks they offer all cater to extreme flex which would definitely eat the factory shaft.

 

[Vanburi]

A little off topic but,
how the hell is you jeep underside so clean?

 

[GATORB8]

@beast40 6 speed?

I would bet the MT case is slightly shorter than the 8AT.

Although my DS is slightly longer than the standard 8AT because of the 4xe tranny, running what I'll assume are the same shocks (Bilstein 5100 3.5-4" at 28.43") I'd hit the trans crossmember right when I'd hit the RZeppa flange. After bending the crossmember on a rock, I was able to make slip joint boot contact with the 5100s.

Note, if the only issue is the RZeppa flange, TF has a replacement high angle RZeppa available now. I needed the thickness reduction and increased DS angle of a double cardon to clear the crossmember.

Stock shaft, even full droop at 28.43, close but no contact:

 

[gonzoflick]

Sounds like a plan! Anyone see any good sales this week for the shaft? Or just hit site directly for $50 off.....

updated..... ORDERED 1350 version.....

Why the 1350 over the 1310? I've read that unless you are running tons the 1350 can actually be too strong and cause major internal gear damage in certain situations other than just snapping a u- joint.

 

[beast40]

A little off topic but,
how the hell is you jeep underside so clean?

It’s a monthish old in that pic. First time off-road at the beach and the shaft cup bent.

 

[rfg9585]

Why the 1350 over the 1310? I've read that unless you are running tons the 1350 can actually be too strong and cause major internal gear damage in certain situations other than just snapping a u- joint.

Guess after discussing with folks at Adams, decide on the 50 instead of 10. Guess time will tell if I made good choice.....

 

[RickyPal]

Wanted to add a data point to this discussion for future searchers.

3.5” lift on a 2024 rubicon XR 3.6 AT running billstein 5100 (24-310635) which are marketed as a 28.4” extended length shock

Bent the flange pretty good and tore the boot despite being under 29” extended length.

Ordering an Adam’s this weekend, but now the JLs do not come with FAD so I will have to play the game of balance castor and pinyon angle

 

[ym0bc1]

Wanted to add a data point to this discussion for future searchers.

3.5” lift on a 2024 rubicon XR 3.6 AT running billstein 5100 (24-310635) which are marketed as a 28.4” extended length shock

Bent the flange pretty good and tore the boot despite being under 29” extended length.

Ordering an Adam’s this weekend, but now the JLs do not come with FAD so I will have to play the game of balance castor and pinyon angle

Genuinely asking - what does FAD have to do with caster and pinion angle?

 

[RickyPal]

Genuinely asking - what does FAD have to do with caster and pinion angle?

I’m just a hobbiest but I will try to explain. The benefit of the FAD is that the front driveshaft does not spin when your jeep is in 2WD, without it, we’re in full time 4WD (2024+ wranglers and all 392 have this design, and anyone else who has purposefully deleted it).

When you have a traditional U Joint style driveshaft, like most aftermarket driveshafts, you need the pinion angle to be pointing toward the transfer case flange such that the double carden does not rotate about any other axis than the transfer case interface axis. The more this angle is off, the more driveline vibration you feel. The kicker is that to achieve this, with most stock axles, you have to have lower than desired caster to avoid bad road manners (because you have to tilt the axle so far forward, lowering your caster.

This is why aftermarket housings offer rotated C’s, and previous Jeep generations people would cut and rotate C’s.

When the FAD does its job, the driveshaft won’t rotate when at highway speeds so you don’t really get the vibration effect. You can cheat and favor desirable caster angle over the ideal pinyon angle.

I and wondering if we will start to see more cut and turns in ‘24+ JLs. I am considering doing it depending on how well I can balance pinyon and caster angles when my driveshaft arrives

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