Locking hubs.. take my money!

[Wheelin98TJ]

Adjust the pinion angle. Vibrations from lifting a Jeep have always been a problem. One way to deal with it is to put locking hubs on it, a much easier and less expensive way is to get adjustable upper control arms and fix the actual problem.

That'll fix the pinion angle problem, but what about the caster angle problem you created?

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[CrazyCooter]

That'll fix the pinion angle problem, but what about the caster angle problem you created?

......and here we go in circles again!

 

[D_JT]

Ya, my Peterbilt with the divider axle deleted and cardan shafts didn't virate either. That's about as relevant to this conversation as talking about a TJ huh?

Actually its completely relevant. Two vehicles with similar set ups. Look under a TJ and a JT, as far as suspension, steering and drive shafts go. They are very similar. They have the same issues when you lift them too. So again. Very relevant and relatable. Jeep never used a FAD from 1991 to 2018. They did change drive shaft designs in 2007 with the JK. But the YJs, TJs, and JKs never had this vibration issue before. So why does the JT with a factory fad delete have a vibration issue? I think that's the bigger question. Also, if the Rzeppa style was truly that much better than a traditional drive shaft, all the aftermarket companies would be building drive shafts with that Rzeppa design.

 

[Stan H]

That'll fix the pinion angle problem, but what about the caster angle problem you created?

Lowers

 

[CrazyCooter]

Actually its completely relevant. Two vehicles with similar set ups. Look under a TJ and a JT, as far as suspension, steering and drive shafts go. They are very similar. They have the same issues when you lift them too. So again. Very relevant and relatable. Jeep never used a FAD from 1991 to 2018. They did change drive shaft designs in 2007 with the JK. But the YJs, TJs, and JKs never had this vibration issue before. So why does the JT with a factory fad delete have a vibration issue? I think that's the bigger question. Also, if the Rzeppa style was truly that much better than a traditional drive shaft, all the aftermarket companies would be building drive shafts with that Rzeppa design.

You are simply incorrect sir.........XJ's, TJ's, WJ's, WK's and JK's have the same vibration issue once they have been lifted beyond a certain point and then driveline speed when gears are swapped out to 5.13's/5.38's amplifies it. TJ Rubi's with the D44 are worse than the D30 equipped vehicles, but that stands to reason when the pinion offset lowers the pinion shaft?

I've even had a TJ with the same vibration issue, but the exact opposite solution where the guy "upgraded" to a high pinion D30 from the OE low pinion with a low CG build and had a vibration that couldn't be dialed in because the pinion was too high to dial in the correct pinion angle without exceeding 10° caster?

The Rzeppa joint is "truly" better at negating vibrations due to joint angles by reducing shaft speed fluctuation. They have their downsides for sure, but I don't see replacing them with a cardan joint shaft as an automatic upgrade for people who drive on the street daily. I experience this in the shop on a semi regular basis. I don't have it with my builds becuse I advise and build around it as to not end up with a bad situation I'm married to.

Ever drive a vehicle equipped with RCV shafts on a steer axle? Probably not, or you wouldn't be arguing these points........

To answer you question.......If Rzeppa joints sucked and didn't serve a good purpose, why would the OE spend the extra money and further complicate things? Certainly the simple, cheaper, cardan joint that has been around and proven since the 1500's would be OE as delivered if they could get away with it?

Same issue, different vehicle, same solution...........Fix the pinion angle (expensive solution to do correctly and keep the caster in spec), stop the driveline from rotating when driving at higher speeds with the FAD or hubs, or possibly some custom double Rzeppa shaft (with reduced droop travel if required).

 

[Stan H]

Actually its completely relevant. Two vehicles with similar set ups. Look under a TJ and a JT, as far as suspension, steering and drive shafts go. They are very similar. They have the same issues when you lift them too. So again. Very relevant and relatable. Jeep never used a FAD from 1991 to 2018. They did change drive shaft designs in 2007 with the JK. But the YJs, TJs, and JKs never had this vibration issue before. So why does the JT with a factory fad delete have a vibration issue? I think that's the bigger question. Also, if the Rzeppa style was truly that much better than a traditional drive shaft, all the aftermarket companies would be building drive shafts with that Rzeppa design.

The total sum of the rotational mass of the now given equation is the problem of the parts are rotating without being locked together in the transfer case it will send out a harmonic vibration . Why because it is contained all in one area and not spread out over the entire druve train. When it is engaged then it is evenly distributed through out the entire system .
The FAD delete is the dumbest thing they have done yet.
My earlier fix ( buying a FAD and installing and wiring to a switch) or
Install Dana 60's .
Any and I mean anytime fix other than what I mentioned is at least 2500.00

 

[CrazyCooter]

The total sum of the rotational mass of the now given equation is the problem of the parts are rotating without being locked together in the transfer case it will send out a harmonic vibration . Why because it is contained all in one area and not spread out over the entire druve train. When it is engaged then it is evenly distributed through out the entire system .
The FAD delete is the dumbest thing they have done yet.
My earlier fix ( buying a FAD and installing and wiring to a switch) or
Install Dana 60's .
Any and I mean anytime fix other than what I mentioned is at least 2500.00

Keep in mind that this vibration isn't an issue until the end user puts everything out of it's designed parameters? From a budgeting/cost cutting standpoint it's brilliant!!!???

Do I want a JT without the FAD? No thanks!

 

[Splenda]

I watched the video. I'm not sure it's worth spending the $3000+ to do this. Just upgrade the entire axle.

 

[Wheelin98TJ]

Lowers

Won't do it.

You can't adjust the pinion angle without impacting caster. Doesn't matter if you're using uppers or lowers.

To adjust the pinion angle, you have to tilt the axle. When you tilt the axle, caster changes.

 

[CrazyCooter]

Won't do it.

You can't adjust the pinion angle without impacting caster. Doesn't matter if you're using uppers or lowers.

To adjust the pinion angle, you have to tilt the axle. When you tilt the axle, caster changes.

Isn't it crazy how hard it is for some to grasp this concept? So much argument to the contrary, but facts will still be facts?

Same goes with offsetting caster side to side.......It's all welded together on a beam style axle, so no "Twisting" will magically take place without breaking something!

 

[Stan H]

Isn't it crazy how hard it is for some to grasp this concept? So much argument to the contrary, but facts will still be facts?

Same goes with offsetting caster side to side.......It's all welded together on a beam style axle, so no "Twisting" will magically take place without breaking something!

So is your stance for or against upper and lowers to change caster to help pinion angle

 

[CrazyCooter]

So is your stance for or against upper and lowers to change caster to help pinion angle

My official stance is:

All adjustable control arms every time so that thrust angle, wheelbase, and axle rotation can be adjusted for optimal results in the best balance of caster, pinion angle and vertical wheel travel. Pinion angle can only be a factor of the best balance it can be adjusted after considering all of the vehicle's build factors.......you can't have it all without also cutting/rotating the knuckles or pumpkin or an aftermarket housing as I posted earlier in this thread.

I don't use the bump spacing or control arm lengths that are supplied in the instructions any quality lift kit that includes adjustable arms and spacers. Everything is optimized for best results.

Additionally I like to use geometry brackets ONLY to improve anti-dive characteristics for those who run heavy or tow and can sacrifice the ground clearance. Caster/pinion angle can be changed with adjustable control arms........

I personally would personally refrain from installing more than maybe a 1.5-2.5" lift on a JT/JL that doesn't have a FAD unless a person is planning to add ta FAD or hubs. I haven't tested it personally, but it "Might" be OK to go taller "IF" a person keeps the OEM front driveline and is willing to run toward to low side of caster as I prefer to do anyway.

I know this is WAY more than you asked for and it's probably going to fly way over your head......But if you do some research on the matter....It can be used to really dial in your rig.

All that said, I'm going to show myself to the exit of this thread.......All the needed info it here IF people would read and comprehend it? I'm not going to waste anymore of my valuable time arguing with people who have no experience in this.

 

[DanJT]

I watched the video. I'm not sure it's worth spending the $3000+ to do this. Just upgrade the entire axle.

My exact thought, maybe I'm just old school. But not that old school!

 

[ShadowsPapa]

I grew up with locking hubs, as well.as the air operated disconnects failing in the 90's as well as many, many posts of fad's failing . My fad works fine but I actually prefer the piece of mind of a manual.

I can connect a fad on the fly with a handful of tools and a hose clamp, but have a locking hub go to pieces................ unless you carry a spare, which i recommend. I had a locking hub blow up on my Ford.

 

[DanJT]

The TJ's had a vibration when lifted, hence the SYE kit and CV drive shaft replacement. The front of JL's and JT's vibrate when lifted is because the transfer case is already rotated up from factory. Best you can do is reset caster to 6-7 degrees positive. With 2.5" lift I set caster to 6 and all is good.
I think, dang pain meds...

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