Aftermarket Driveshaft Mega Thread…Buyer Beware

[AnnDee4444]

Thought about this some more. If caster shims at the ball joints were to become a product, the most you could get would be approximately 2-2.5 degrees additional caster. The top shim would need to account for both caster & camber, while the bottom could just be for caster only.

When looking at driveshaft angles, lowering the caster 2.5 degrees would be like lowering the ride height about 1.5".

edit: submitted a product request for camber shims to SPC. If anyone else wants to help: https://www.spcalignment.com/corporate/contact-us

Of course ball joints are also an option. These are for the JK: https://www.spcalignment.com/component/content/article?id=373#:~:text=Rear Replacement Part-,Pin Joints,Ball Joint Press for removal and installation of these pin joints.,-23510 - Cam

SPC replied: ball joints aren't possible, and caster shims would do nothing due to their location in the hub... not the C like I was thinking earlier

Yeah, nice idea, but caster can’t be changed with sleeves. Please see the attachment. It is of a JL front axle with the knuckle removed. I picked this one because it was the best image from this report to show why caster cannot be changed with the sleeves. The upper ball joint is pressed into the top of the axle C and the lower ball joint is pressed into the bottom of the C. Those are the pivot points in the front axle which determine caster (and SAI, etc). The sleeves change camber in the positive direction by pushing the top of the knuckle out. Makes sense. But if we offset the hole in the sleeve forward or backward, we are rocking the knuckle around but we have NOT changed caster a bit. You have to change a pivot point to change caster. The sleeves won’t do that. The previous 2 generations of Wrangler allowed us to use an offset upper ball joint to change the caster. Jeep did not leave enough room to do that here. The 82375 cam bolts (and any adjustable front control arms) change camber by rocking the whole axle which also affects pinion angle. At this time, there’s no way to separate caster change from pinion angle change without reorienting the axle Cs. Plus, cam bolts (and adjustable arms) can only provide the same caster change on both sides; no individual caster change is available.​

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Sorry to rain on your parade, but caster change just isn’t that easy!​

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[supermike]

just installed the Adam's 1350 front driveshaft. With 6 degree of caster, 2.5 in lift, I have slight vibration above 72 ish mph......doesn't seems to worse if speed increased through out 97 mph....

Why nobody makes CV ball bearing style shaft? Is it because of cost?

 

[MSparks909]

just installed the Adam's 1350 front driveshaft. With 6 degree of caster, 2.5 in lift, I have slight vibration above 72 ish mph......doesn't seems to worse if speed increased through out 97 mph....

Why nobody makes CV ball bearing style shaft? Is it because of cost?

Probably. Teraflex makes a high angle CV driveshaft for the JK. Wish they made one for the JL but in all honesty it’s such a small percentage of owners that have this issue it’s not cost effective for them to do so. You could try backing caster down to 4.5-5 degrees or so to see if that helps.

 

[AnnDee4444]

Why nobody makes CV ball bearing style shaft? Is it because of cost?

OEM is a rzeppa joint... so I doubt it's cost.

I could see how the double-cardan would have a higher operating angle than the some rzeppas, so maybe that's the reason.

 

[supermike]

OEM is a rzeppa joint... so I doubt it's cost.

I could see how the double-cardan would have a higher operating angle than the some rzeppas, so maybe that's the reason.

IF RCV makes drive shafts.........

 

[Remorseless]

Just a note on the full time non-392 models. Both the FAD and 2wd are available, although 4 auto does lock the FAD.

For some information on discussion. I measured driveshaft angle at the ear of the pinion side U-joint now that I have a 1310 shaft installed. I probably should do it on the shaft itself, but comparing to my earlier picture with the stock shaft (same MC 3.5 setup) the lower U-joint angle appears to have maintained approximately 10* of angle from plumb. Surprising, as I would thing the longer DC CV would increase the angle compared to the stock RZ.

While the DC section is longer, it does allow for some angle, and I'm willing to bet the axle flange portion is shorter than the stock shaft. Would be how I'd think they'd make up the differences.

 

[supermike]

Probably. Teraflex makes a high angle CV driveshaft for the JK. Wish they made one for the JL but in all honesty it’s such a small percentage of owners that have this issue it’s not cost effective for them to do so. You could try backing caster down to 4.5-5 degrees or so to see if that helps.

you are right, just like your set up before,,,,,,I lengthen the upper control arm and level out that pinion angle...still vibrates... funny thing is, my jeep felt more stable running 4 degrees of caster than 6..

 

[Some Random Guy]

So, I have a UD44 being delivered and have been thinking about this potential issue. I also have Sport driveshafts, so I contacted a local driveline shop. They want me to bring my stock shafts in so they can design new ones. They did say flat out that you cannot run CV’s on both sides, so it looks like I’ve got some learning to do. I am seriously considering taking the axle to have caster added before I mount it to stay ahead of driveline vibrations. However, it’s not a daily driver so I’m hesitant to dump big bucks into that.

 

[MSparks909]

So, I have a UD44 being delivered and have been thinking about this potential issue. I also have Sport driveshafts, so I contacted a local driveline shop. They want me to bring my stock shafts in so they can design new ones. They did say flat out that you cannot run CV’s on both sides, so it looks like I’ve got some learning to do. I am seriously considering taking the axle to have caster added before I mount it to stay ahead of driveline vibrations. However, it’s not a daily driver so I’m hesitant to dump big bucks into that.

Does the UD44 have the same caster offset as a stock JL front axle? Or is it caster corrected?

 

[Some Random Guy]

Does the UD44 have the same caster offset as a stock JL front axle? Or is it caster corrected?

I can’t find anything stating the JL one is caster corrected. I can for the JK UD44. I plan to measure when it gets here. Not sure how much it would cost, but maybe it would be reasonable price if the axle isn’t on the jeep yet.

 

[MSparks909]

I can’t find anything stating the JL one is caster corrected. I can for the JK UD44. I plan to measure when it gets here. Not sure how much it would cost, but maybe it would be reasonable price if the axle isn’t on the jeep yet.

I’d only do that if you find a *really* good shop that’s done that a few times. You would have to grind off & re-weld the C’s on the axle…a degree off on either end would cause huge alignment issues. Definitely not a mod I’d want to do to a brand new axle.

 

[Some Random Guy]

UD44 for the JL is not caster corrected. I was fairly sure, but it is confirmed with measurements now. I’m at a low enough lift I’ll probably reduce caster to keep driveline from vibrating too bad. We’ll see what my local driveline shop comes up with though.

 

[Wicked3.0]

I had about 6.5 castor after installing Metal Cloak 3.5 Game Changer and all was good with stock driveshaft, however, I could not flex it fully with the Metal Cloak 6 pak shocks without the front driveshaft bottoming out at CV joint by transfer case. It was definitely not going to hold up off-roading. So I upgraded to Tom Woods 1350 front driveshaft and had a vibration from 48mph-65mph, and also a shudder/strong shaking vibration WOT at 14mph. If I keep the Jeep in Force Rear Wheel Drive with JL Tazer, vibration is gone at all speeds, however I did not feel comfortable running like this all the time long-term with stock axels.

So I thought it was the Tom Woods driveshaft that was not balanced. Turned out the driveshaft was perfectly balanced. I then adjusted Castor to about 4.2 (thank you OP for the advice and this thread, I learned a lot). I extended upper control arms by 6 full turns and shortened lower control arms 2 full turns and now have a Castor of 4.2. Jeep handles way different but vibration is completely gone. Steering feels more "squishy" but it tracks straight on highway and does not wander at high speeds. Jeep wanders more at low speeds around 30mph-40mph than before, but I can accept the trade off that the vibration is not present. I have my Falcon Steering Stabilizer set at "Medium" and that helps with the responsiveness of the steering. The angle of the driveshaft was at 10 degrees before and now its sitting at 7.7 degrees. Pinion is about 2.5 degrees.

I might experiment and see if I can adjust the upper and lower control arms in the middle between 6.5 - 4.2 castor to see if maybe it can be in the middle and still not have the vibration. We shall see. Thanks again for everyone's input, the vibration was driving me nuts.

 

[Jphipps]

I bought the jeep that aggiechris used to own and going to try and tackle the vibration issue. If im running a game changer 3.5" lift how much would swapping to 2.5" springs help? In the next few weeks I plan on adjusting the caster from 5.8 down to 4ish to see if that helps. Running 5.8 and swapping the 1350 adams out for a stock shaft didnt do anything.

 

[MSparks909]

I bought the jeep that aggiechris used to own and going to try and tackle the vibration issue. If im running a game changer 3.5" lift how much would swapping to 2.5" springs help? In the next few weeks I plan on adjusting the caster from 5.8 down to 4ish to see if that helps. Running 5.8 and swapping the 1350 adams out for a stock shaft didnt do anything.

Interesting the stock shaft didn’t help. Sorry to hear that. I’d imagine dropping 1” of lift would help some but hard to say how much. Try adjusting caster to 4-4.5 with the stock driveshaft.

If that still doesn’t help you might have to spring for a caster corrected front axle housing. Can pick up a Dynatrac Pro Rock 44 Unlimited axle for around $6K…

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