Bad Vibration after Front Driveshaft Install

[WILDHOBO]

Man I've got a complete D44 that I removed from my Willys when I installed my Rubi axles. Problem is they're not the wide track. But then again, does that extra 1-1/2" really make that much difference? Probably not but my rcv axles wouldn't work with them so there's that. I've already got another wide track rear D44 sitting in the shop that I'm trying to decide what to do with.

Apparently I should have stopped by when I just passed through last month.

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[JTenn]

Apparently I should have stopped by when I just passed through last month.

Absolutely should have!!

 

[WILDHOBO]

Absolutely should have!!

It was a whirlwind. Got to a friends place near gattlinburg after 11pm Saturday night. Did Windrock the next day, amd headed towards home on Monday.

 

[ospreyfe55]

Well I spoke to Adam's yesterday and they basically gave me 2 options! Option #1 Lower the Jeep! WTF! and Option #2 adjust the pinion to match the driveshaft and deal with the shitty steering! While I get they have no control over the adjustments and what is built in, but not even a you can return it if your not happy, I would even pay a restocking fee at this point just to try a salvage the $700 spent! Not mention repairing my factory unit. And then look at replacing shocks to limit the amount of down travel.

I can now say that when I hear anyone asking about replacing their Front DS I will do everything in power to talk them out of it. Again I have spent a lot of money on my rig and I am very methodical when it comes to how I spend my money on my Jeep and this purchase took the wind out of my sails and by far the worst purchase made! Maybe I can recoup some of the cash by listing it on FB!

 

[Wheelin98TJ]

Have you tried adjusting the pinion angle until the vibes are gone and then measure your caster? Or do you have a rough guess what you're ending caster would be if you did this?

 

[ospreyfe55]

Have you tried adjusting the pinion angle until the vibes are gone and then measure your caster? Or do you have a rough guess what you're ending caster would be if you did this?

Well I started with 6.5 degrees of caster and the starting UCAs measurements were 19.75”. After talking to MC, every full rotation is .75 degree of caster at 1/8” I adjusted all the way to 20.375” (20-3/8”) which would be roughly 3.75 degrees taken out which would have put me roughly at 2.75 degree of caster! It drove like crap and darted all over the place at lower speeds.

 

[WILDHOBO]

Well I spoke to Adam's yesterday and they basically gave me 2 options! Option #1 Lower the Jeep! WTF! and Option #2 adjust the pinion to match the driveshaft and deal with the shitty steering! While I get they have no control over the adjustments and what is built in, but not even a you can return it if your not happy, I would even pay a restocking fee at this point just to try a salvage the $700 spent! Not mention repairing my factory unit. And then look at replacing shocks to limit the amount of down travel.

I can now say that when I hear anyone asking about replacing their Front DS I will do everything in power to talk them out of it. Again I have spent a lot of money on my rig and I am very methodical when it comes to how I spend my money on my Jeep and this purchase took the wind out of my sails and by far the worst purchase made! Maybe I can recoup some of the cash by listing it on FB!

I wouldn’t worry about shock droop. That’s typically going to be a slower off road speeds with the swaybar disconnected. You won’t hurt anything there I wouldn’t think. I think the issue is highway driving. I think you’ll have no problem selling it to someone who only uses 4wd at slow speeds. Just don’t sell it to a 4hi auto owner.

 

[PuddleJumper]

with all this info out. Does anyone know a high speed shaft solution for the front? odds are i'll end up with 2in lift but lots of travel. but i like to hit 60 plus in 4hi.

 

[WILDHOBO]

Well I spoke to Adam's yesterday and they basically gave me 2 options! Option #1 Lower the Jeep! WTF! and Option #2 adjust the pinion to match the driveshaft and deal with the shitty steering! While I get they have no control over the adjustments and what is built in, but not even a you can return it if your not happy, I would even pay a restocking fee at this point just to try a salvage the $700 spent! Not mention repairing my factory unit. And then look at replacing shocks to limit the amount of down travel.

I can now say that when I hear anyone asking about replacing their Front DS I will do everything in power to talk them out of it. Again I have spent a lot of money on my rig and I am very methodical when it comes to how I spend my money on my Jeep and this purchase took the wind out of my sails and by far the worst purchase made! Maybe I can recoup some of the cash by listing it on FB!

Also, fwiw, I don’t think your steering will be bad. Just not as good as higher caster, but there’s a big range of caster angles that work just fine. I’m sure I’m not much better than 5 degrees with a 4” lift and it steers beautifully.

 

[WILDHOBO]

with all this info out. Does anyone know a high speed shaft solution for the front? odds are i'll end up with 2in lift but lots of travel. but i like to hit 60 plus in 4hi.

The high speed solution is just to change the pinion angle to a nice middle ground between caster and drive shaft angle. If you don’t use 4wd at fast speeds, you can adjust for higher caster. If you do, just favor pinion angle. It’s all how you use your jeep.

 

[ospreyfe55]

I wouldn’t worry about shock droop. That’s typically going to be a slower off road speeds with the swaybar disconnected. You won’t hurt anything there I wouldn’t think. I think the issue is highway driving. I think you’ll have no problem selling it to someone who only uses 4wd at slow speeds. Just don’t sell it to a 4hi auto owner.

Ok good to know on the shocks. I just don’t know what exactly I will do. I don’t use 4hi in lot of times but the fact this now just takes one limit off the table when it’s capable of doing it with the stock shaft.

 

[ShadowsPapa]

Also, fwiw, I don’t think your steering will be bad. Just not as good as higher caster, but there’s a big range of caster angles that work just fine. I’m sure I’m not much better than 5 degrees with a 4” lift and it steers beautifully.

I wouldn't want any less than 4 degrees. Not on these and not with the larger tires.

With a stock driveshaft where the output and pinion shafts are parallel, the maximum shaft angle is 15 degrees.
7 degrees joint angle is a recommended max (for highway speeds)
Consider these are single cardan joints without a second joint to take out driveshaft speed fluctuations, you really need to be keeping it down, in fact, just off of straight (about a degree) is recommended for joint life.

He can do some math, figure the shaft angle, the joint angle, where the pinion is at vs. caster, but frankly, for a street driven Jeep, no way I'd take it down to 4 degrees of less caster if it was 80% street/highway. No way.

 

[WILDHOBO]

Ok good to know on the shocks. I just don’t know what exactly I will do. I don’t use 4hi in lot of times but the fact this now just takes one limit off the table when it’s capable of doing it with the stock shaft.

For me, the issue is only when using 4hi auto at sustained interstate speeds. I have zero concerns about occasionally hitting 40mph for short stretches (seconds or minutes) offroad. That’s not enough time to do much if any damage. The shafts can also handle terrible angles just fine when going slowly off road. It’s just for moments of high articulation. It’s not sustained.

 

[PuddleJumper]

The high speed solution is just to change the pinion angle to a nice middle ground between caster and drive shaft angle. If you don’t use 4wd at fast speeds, you can adjust for higher caster. If you do, just favor pinion angle. It’s all how you use your jeep.

I would hope a double cardon at the TC would be enough but I'm worried i may have to run limiting straps to jump safely. I don't have any issues stock but i'll have a fair bit more stroke with Fox elites and i do like having lots of caster. its starting to look like 6 will be the max.

 

[ShadowsPapa]

The shafts can also handle terrible angles just fine when going slowly off road. It’s just for moments of high articulation.

But the joints will give out sooner. The joints are only rated for so many degrees, regardless, due to the intense stresses - instead of turning the shaft, it's trying to move things sideways.
Too much and it will pop the joint, even if he never ever used it on the highway.
It's a good reason to carry spare joints (like someone here does)

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