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Discussion Starter #1
Tonight I noticed a little vibration under acceleration. I'm wondering if it's anything I should be concerned with. I put my Clayton 3.5" lift on about two weeks ago; however, I really only have about 30 miles since then. I replaced both of the drive shafts with JE Reel 1350 shafts.

Everything has been smooth until tonight. I noticed it at about 40 MPH, but after stopping and accelerating again it wasn't there. I took it for another drive later and it wasn't there and then was there. Any idea what that could mean? I can feel it in the seat and the steering wheel.
 

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Could be any number of things, but the most likely two are a nut/bolt that isn't torqued down (in particular the track bars and control arms) or bad pinion angle. First thing I'd do is check all the nuts/bolts, then take a look at your pinion angles. The rear is pretty easy to get right, but I've found that anything much over 5° on the front will cause vibration at certain speeds with UJ driveshafts.
 

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Discussion Starter #3 (Edited)
I've already gone back in to have them fix the rear pinion angle, so hopefully that isn't it. Of course there was no vibration then. Can you even adjust the front pinion angle? For some reason I was thinking you couldn't or shouldn't do that.

Is a slight vibration like this something I should worry about? Will it damage my drive shafts or something else down the line?
 

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I've already gone back in to have them fix the rear pinion angle, so hopefully that isn't it. Of course there was no vibration then. Can you even adjust the front pinion angle? For some reason I was thinking you couldn't or shouldn't do that.
Adjusting the front is more tricky as you have to balance pinion angle with caster angle, but somewhere in the middle will be a compromise that provides enough caster and reduces the pinion angle to the point there is no vibration.


Is a slight vibration like this something I should worry about? Will it damage my drive shafts or something else down the line?
Good question, some say yes, some say no. I don't like to have part of the vehicle vibrating, but I know people who've driven around with pretty noticeable driveline vibration for a lot fo miles with no problems. You do run the risk of wearing out UJ's and pinion bearings faster, but a very slight vibration is not going to be a big issue in my view.

The easiest way to check is to remove the front drive shaft and drive it around and see how it feels. If the vibration is still there then you will at least know it isn't the drive shaft, if it goes away you will know for sure it is the driveshaft and very likely pinion angle.
 
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Mine vibrates ever so slightly between the 50 MPH and 55 MPH band. I thought it was ok but now I’m not so sure.

Interestingly, I just had a JE REEL fail on me, the socket thing that holds the ball in the double cardon on the front drive shaft got hosed. My t-case went out at the same time and it’s unclear what broke first taking out the other component.

I put another JE REEL shaft on mine (which vibrates in the same way) and I’ll be following JE REEL shaft failures closely to see if there is a pattern.
 

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Discussion Starter #6
Thanks for the information Phil. I called Clayton Offroad to see if what they have seen as far as vibrations. The consensus is that the problem is probably the drive line. He said if something was loose it would probably vibrate all of the time and not just under acceleration. He suggested removing the drive shafts individually to see if that eliminates the vibration too. A final frightening point he made was that he saw two people use JE Reel drive shafts and both had failures.
 
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I'm using the JE Reel shafts (1350's) and have the vibration from the mid 40's to mid 50's (speedometer speed, actual speed is higher due to 35's). It started off as a barely perceptible vibration right after installation but has gotten progressively worse. I've been somewhat ignoring it but will need to begin investigating soon. I have been hearing quite a bit of negative information regarding JE Reel here. I don't know if it represents a true problem with their shafts or not. I'll be interested in seeing how the consensus progresses on this one.
 

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A final frightening point he made was that he saw two people use JE Reel drive shafts and both had failures.
I've got 30k miles on my JE Reel shafts with no problems. I suspect some of the failures at least may be due to people setting caster to +5° or so, which I know some people are doing, this will result in a really bad pinion angle and whether they feel it or not will be wearing the shaft components badly.

The other thing people forget is that the UJ's and double cardan centering ball need to be greased. I replaced my UJ's with Spicer sealed for life ones so I didn't have to mess with greasing them. The centering ball grease points are nigh on impossible to get to with the shafts in place, so I pull the shafts every 6 months or so and lube them.

It is definitely something worth watching though, as I've always felt the front drive shaft angle at the front of the t-case is pretty high.
 

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Interestingly, I just had a JE REEL fail on me, the socket thing that holds the ball in the double cardon on the front drive shaft got hosed. My t-case went out at the same time and it’s unclear what broke first taking out the other component.
The more I think about it, the more confused I get :shaking: The t-case front shaft is only turning because the driveshaft turns it, so if it were to stop turning due to the driveshaft failing and seizing, the front R&P or the driveshaft itself would fail. Apart from possibly wearing the t-case shaft bearings, which wouldn't cause the t-case to fail like yours did, a failed shaft should not cause the t-case to grenade, as the t-case doesn't care if the front shaft is turning or not when in 2WD.


I put another JE REEL shaft on mine (which vibrates in the same way) and I’ll be following JE REEL shaft failures closely to see if there is a pattern.
First thing I would do is pull the shaft to make 100% sure it is the shaft, although I suspect it is, then I would start extending both the upper control arms by 0.050" (about 1 full turn) at a time until the vibration goes away. The problem is that you start losing caster and the vehicle won't track as well, but I found the point just before the vibration starts is bearable in terms of caster on my vehicle.
 

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Discussion Starter #10 (Edited)
What would be a good caster angle? I think Adam at Clayton Offroad mentioned 4.5°, but I may not be remembering correctly. It does sound like as it is that I'm okay driving it a bit until I get this fixed although I'm not going to waste any time doing so. The shop cannot fix it tomorrow, but they're going to look at it.
 
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The more I think about it, the more confused I get :shaking: The t-case front shaft is only turning because the driveshaft turns it, so if it were to stop turning due to the driveshaft failing and seizing, the front R&P or the driveshaft itself would fail. Apart from possibly wearing the t-case shaft bearings, which wouldn't cause the t-case to fail like yours did, a failed shaft should not cause the t-case to grenade, as the t-case doesn't care if the front shaft is turning or not when in 2WD.
But if the t-case front shaft seized for some reason, it could definitely take out the U-Joint.
 
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The centering ball grease points are nigh on impossible to get to with the shafts in place, so I pull the shafts every 6 months or so and lube them.
I agree that it is really tough to get at the front centering ball grease joints. I have found with mine, though, that if I just disconnect the front shaft at the axle end and lift the front end of the shaft up fairly high (I usually just block it up with an old 4 x 4), then I can get at the center grease joint. Not a big deal but it does save a little bit of work, though I wish they were designed to be easier to get at.
 

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But if the t-case front shaft seized for some reason, it could definitely take out the U-Joint.
Definitely, if the problem started in the t-case and that front output shaft seized, it would demolish a UJ instantly. Which is better than having the R&P fail.
 

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What would be a good caster angle? I think Adam at Clayton Offroad mentioned 4.5°, but I may not be remembering correctly.
It will vary with the amount of lift you have etc. With 4.5" of lift I can't get better than 2.5° or so with getting drive shaft vibration. It definitely steers and drives better at 4.5°, but I'd rather sacrifice a little caster to get the drive shaft vibration free. Factory spec for caster is +4.2° ±0.5°.
 

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Discussion Starter #16
It will vary with the amount of lift you have etc. With 4.5" of lift I can't get better than 2.5° or so with getting drive shaft vibration. It definitely steers and drives better at 4.5°, but I'd rather sacrifice a little caster to get the drive shaft vibration free. Factory spec for caster is +4.2° ±0.5°.
Thanks you've been a tremendous help.
 

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Speaking of grease. What grease are you guys using for your u joints and control arms?
I tried Mobil 1 a while ago, but found it "melted" easily and used to get red liquid (looked like ATF) leaking from joints etc. So I switched to Castrol Pyroplex Blue #2, as it does not washout when wet and actually become tackier offering better protection. It also doesn't "melt" like the Mobil 1 and stays in place very well. It is a lithium complex grease and meets NLGI Grade 2 EP, which is what is called for by the service manual.

http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=82915556&contentId=7022499
 
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Maybe my DS and t-case just happened to break around the same time coincidently becuase it does not really make sence to me either Phil. Now I’ve replaced both I’ll be keeping an eye on them.

What’s the best way to check caster? I think mine was at 5° but I’ll check it later when I get home.
 

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I tried Mobil 1 a while ago, but found it "melted" easily and used to get red liquid (looked like ATF) leaking from joints etc. So I switched to Castrol Pyroplex Blue #2, as it does not washout when wet and actually become tackier offering better protection. It also doesn't "melt" like the Mobil 1 and stays in place very well. It is a lithium complex grease and meets NLGI Grade 2 EP, which is what is called for by the service manual.

http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=82915556&contentId=7022499


Thanks PhilD. My drive shaft I bought from you will be here tomorrow and I'm gonna grease everything while I'm at it. I've been using Mag 1 Super Lithium Moly Grease. It's black.

My caster is at about 5.5 degrees. I've been running the stock shaft. I'm sure I'll have to adjust a little out. I'll let you guys know what I end up with.

I'll try the Castrol, thanks again.
 

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Maybe my DS and t-case just happened to break around the same time coincidently becuase it does not really make sence to me either Phil. Now I’ve replaced both I’ll be keeping an eye on them.
I'm pretty sure one caused the other to break, as already discussed a failed DS shouldn't front cause catastrophic failure of the t-case, but a failed t-case would likely cause catastrophic failure of the DS. Which then leaves us wondering why the rear DS didn't fail also. If I were to guess Id say the t-case is 70% likely the cause of the failure.

As a rule a DS on the way out will create a rumbling vibration, a t-case output shaft would likely be screeching/scraping sounds, at least if it was the bearing.



What’s the best way to check caster? I think mine was at 5° but I’ll check it later when I get home.
No easy way I'm afraid without getting an alignment done, measuring across the flat of the lower part of the knuckle will give you a good idea.

If you have a caster cage and turntables you can measure it on the end of the axle shaft by turning the wheels 20° each way, but that's a pain and I don't think necessary.

I would use the flats off the bottom of the knuckles or the tops of the upper ball joints.

First rotate the front pinion so that the ear that is attached to the yoke is horizontal (parallel with the ground), then measure the angle of it. Measure the angle of the DS, and subtract the angle you took off the pinion to give you the pinion angle. If this is much over over 5° you will need to lower it.

To lower the pinion angle you will need to either extend the upper control arms or shorten the lowers, I prefer to lengthen the uppers but you have to watch out that your springs don't get too close to the sway bar links. Lengthen the uppers by exactly the same amount each side, until the pinion angle is 5° or less, every time you check it re-measure the DS angle as it will change slightly.

Now go take it for a drive and check for two things, first driveline vibration, and second how it steers. If the driveline vibration is still there you need to lower the pinion angle more. Once you get rid of the vibration you'll likely not appreciate the light steering feel, so start increasing the pinion angle (no more than one turn on each control arm adjuster), and keep testing. You will find a point that the vibration is all but gone, and the steering is acceptable, and that is as good as you are going to get without rotating the knuckles.

Make sure you have pad and pen handy and record all angles and adjustments. That way it will be much easier to step back if you need to.

It sounds more complicated than it is and doesn't actually take that long, less than 60 mins start to finish.

Before you start you should actually measure the wheelbase (center of hub to center of hub), it should be 116", mine is 116.5". If it is off by much you should take care of that first.
 
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