Vibration - Drive shaft?

ERAUGrad04

Caught the Bug
Hi all!

Looking for a little input on a slight vibration that I have been chasing since installing my lift and tires. The vibration comes on around 50mph and gets stronger the faster I go. To be fair, the vibration is slight, but noticeable.

The Jeep is a 2014 Unlimited Rubicon with about 1,500mi on it. The lift setup is a 3.5AEV with the 5160 Bilsteins along with the Fox ATS steering stabilizer, Dynatrac ball joints and a Synergy track bar. The tires are 35" BFG KM2s mounted on 17" AEV Pintler wheels. I did all the mods within about 100th of being new.

I've had the tires balanced probably 5 times now including a road force balance on a Hunter 9700 balancing machine. Everything points to the tires being balanced.

I'm starting to wonder if I have a driveline vibration. The front drive shift is stock and has not been off road yet. I know the front DS is prone to the boot failing on the taller lifts and is currently on my radar for replacement.

All said, are the factory shafts prone to vibration at lift heights similar to mine? I am thinking about pulling the front DS this afternoon and see how it rides, but was curious if anyone has any thoughts or similar experiences.

Maybe I am just expecting a smoother ride from a 3.5" lift and 35" mud terrains. If that's the case, just tell me and I'll get over it and go have a beer! :)

Thanks all!
ERAU
 
Is the vibration coming from the steering wheel or the jeep its self

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Buster3479

Member
Pull the front driveshaft and take it for a ride. It won't cost you anything but a little time. I installed a 3.5 RS over a year ago and had tire balance issues. It always happened between 50 and 57 mph. It sounds like you've covered that (took a road force for me to do so). I later had vibes from a front 1310 driveshaft I didn't seat properly, but that was a very different feeling. Check your track bar bolts for tightness while you're under there (more death wobble than vibration).
 

wayoflife

Administrator
Staff member
If you're still running a factory front shaft, I doubt that's where it's coming from. But, just to be sure, does the vibration oscillate or is it constant at that speed?
 

ERAUGrad04

Caught the Bug
Pull the front driveshaft and take it for a ride. It won't cost you anything but a little time. I installed a 3.5 RS over a year ago and had tire balance issues. It always happened between 50 and 57 mph. It sounds like you've covered that (took a road force for me to do so). I later had vibes from a front 1310 driveshaft I didn't seat properly, but that was a very different feeling. Check your track bar bolts for tightness while you're under there (more death wobble than vibration).

I just re-torqued all of the suspension bolts about 500 miles ago and paint lined all nuts/bolts while I was at it.

I am kinda thinking it is still a tire issue, but just trying to rule out all other options.

Thanks for the suggestion on the DS. I should get a chance to pull the DS later this week.
 

ERAUGrad04

Caught the Bug
If you're still running a factory front shaft, I doubt that's where it's coming from. But, just to be sure, does the vibration oscillate or is it constant at that speed?

With the factory shaft, I really don't expect it to be the source of the vibration like you say.

I would say that it is relatively constant, but minimal. I am starting to think that I am just chasing the slight vibration that is to be expected with 35" MTs....

As a side note Eddie, I think I remember seeing you are down in the SoCal area and it looks like we are just going to miss you guys. We are headed down to the LA area tomorrow with a stop off in Pismo Beach.

Next time you guys find yourself in the Bay Area, let me know! :)

Morgan
 

wayoflife

Administrator
Staff member
Okay, if it were really your front drive shaft, the vibration would oscillate like a sine wave. If it's relatively constant, it's most likely something else - maybe you're feeling the lug thumps of your MT's.

Also, we're back up north now and will have to get some kind of run going soon.
 

Sithwindu

Member
Okay, if it were really your front drive shaft, the vibration would oscillate like a sine wave. If it's relatively constant, it's most likely something else - maybe you're feeling the lug thumps of your MT's.

Also, we're back up north now and will have to get some kind of run going soon.

Yeah I think it's your mt's brotha. I have mud grapplers and feel a slight vibration but it's from the aggressiveness of the tire.
 
Did you road force those puppies ?
Up Until my last balance .. I always had a small vibe at 60-70. Last shop was finally able to fix it. I will be going back there again.
I'm guessing tires too.
 

ERAUGrad04

Caught the Bug
Okay, if it were really your front drive shaft, the vibration would oscillate like a sine wave. If it's relatively constant, it's most likely something else - maybe you're feeling the lug thumps of your MT's.

Also, we're back up north now and will have to get some kind of run going soon.

So it's funny you mention the vibration oscillating. Yesterday we had our first long road trip (SF Bay to LA) and noticed the vibration would come and go... Almost cyclical. There were times when it felt smooth as glass and other times it was really noticeable.

Just curious, what would make a vibration oscillate? Two tires opposing each other getting in/out of sync? It seemed to oscillate when while driving in a straight line.

Thanks again everyone for the input!
ERAU
 

Brankz

New member
I had a grinding noise and a lil vibration, changed my ds, I use a 09 2 door one and it's gone :thumbs: got the DS for 10 bucks and a 18 pack of Modelo beer lol they help me installed
 

ERAUGrad04

Caught the Bug
If you're still running a factory front shaft, I doubt that's where it's coming from. But, just to be sure, does the vibration oscillate or is it constant at that speed?

So after almost 1,000mi road trip, I really noticed that the vibration (and almost a faint droning/humming noise associated with it), seems to oscillate. It will even oscillate driving on a straight stretch of interstate.

The interesting thing about this vibration is it seems to come and go. For example, I can get on the interstate by my house and push it up to 65-70 and it seems smooth as glass. But once at speed for a few miles (maybe 5-7mi), the vibration/noise starts to appear and sticks with me.

I get home from a work trip on Thursday and plan on pulling the front shaft.

Any additional thoughts?

Thanks!
 

wayoflife

Administrator
Staff member
So after almost 1,000mi road trip, I really noticed that the vibration (and almost a faint droning/humming noise associated with it), seems to oscillate. It will even oscillate driving on a straight stretch of interstate.

The interesting thing about this vibration is it seems to come and go. For example, I can get on the interstate by my house and push it up to 65-70 and it seems smooth as glass. But once at speed for a few miles (maybe 5-7mi), the vibration/noise starts to appear and sticks with me.

I get home from a work trip on Thursday and plan on pulling the front shaft.

Any additional thoughts?

Thanks!

What gear ratio are you running? Can you see any visible dents in your drive shaft or see if any of the weights have been knocked off? How about the CV boot at the output shaft - any signs of it spitting grease out? How does the u-joint at the pinion look? Short of seeing it for myself, I'd really need to know a lot more before I could give additional thoughts. Typically, a factory front shaft will NOT vibrate unless something is off with one of the things I just mentioned. Of course, vibrations typically only occur with a higher gear ratio as well.
 

ERAUGrad04

Caught the Bug
What gear ratio are you running? Can you see any visible dents in your drive shaft or see if any of the weights have been knocked off? How about the CV boot at the output shaft - any signs of it spitting grease out? How does the u-joint at the pinion look? Short of seeing it for myself, I'd really need to know a lot more before I could give additional thoughts. Typically, a factory front shaft will NOT vibrate unless something is off with one of the things I just mentioned. Of course, vibrations typically only occur with a higher gear ratio as well.

The factory shaft I have new condition with no signs of missing weights or dents. The boot is in new condition as well with no signs of grease being expelled.

The gears are factory 4.10s turning 35" Bfg KM2s.

When I got it aligned a month or so ago, my caster came in right at 4.2°, which leads me to believe the pinion is at 1.8°.

I think it's time I just bite the bullet and pull the front DS just so I can rule it out.

As for tire balance, they have been balanced a few times with a Hunter GSP9700 Road Force machine. When first mounted, they were road forced and the numbers all came in very low. Discount Tire is just telling me that is what I should expect with a 35" Mud.

Thanks for the input Eddie!
 

09blackruby

Member
I'm experiencing what seems to be the same type of a vibration from about 50-57ish. 2.5 inch lift and those darn aev correction brackets, stock ds. I was thinking I may have to much castor and getting front ds vibs. Could this also be the case? A picture from the top of the upper ball joint:

ImageUploadedByWAYALIFE1407282903.245001.jpg

I don't want to hijack this thread but I'm just wondering if my thinking is correct? If so, I was thinking of ditching the brackets and getting Currie adjustable lowers to fix. If I'm correct could this also be his issue?
 
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wayoflife

Administrator
Staff member
The factory shaft I have new condition with no signs of missing weights or dents. The boot is in new condition as well with no signs of grease being expelled.

The gears are factory 4.10s turning 35" Bfg KM2s.

When I got it aligned a month or so ago, my caster came in right at 4.2°, which leads me to believe the pinion is at 1.8°.

I think it's time I just bite the bullet and pull the front DS just so I can rule it out.

As for tire balance, they have been balanced a few times with a Hunter GSP9700 Road Force machine. When first mounted, they were road forced and the numbers all came in very low. Discount Tire is just telling me that is what I should expect with a 35" Mud.

Thanks for the input Eddie!

Wow, being that's the case, I find it VERY DIFFICULT to believe that you have a front drive shaft that's vibrating. Pull it! Only way to be sure but, I seriously doubt it's the source of your vibration.
 

wayoflife

Administrator
Staff member
I'm experiencing what seems to be the same type of a vibration from about 50-57ish. 2.5 inch lift and those darn aev correction brackets, stock ds. I was thinking I may have to much castor and getting front ds vibs. Could this also be the case? A picture from the top of the upper ball joint:

View attachment 94456

I don't want to hijack this thread but I'm just wondering if my thinking is correct? If so, I was thinking of ditching the brackets and getting Currie adjustable lowers to fix. If I'm correct could this also be his issue?

If you're running drop brackets with just 2.5" of lift, yeah, you have way more caster than you need. However, IF you're still running factory gears and a factory shaft, you really shouldn't be seeing vibrations.
 

09blackruby

Member
If you're running drop brackets with just 2.5" of lift, yeah, you have way more caster than you need. However, IF you're still running factory gears and a factory shaft, you really shouldn't be seeing vibrations.

Yes factory gears and ds. Thank you for the quick response.
 

wayoflife

Administrator
Staff member
Yes factory gears and ds. Thank you for the quick response.

Yeah, that being the case, you shouldn't be seeing vibrations. The factory shaft does have a u-joint at the pinion but the rzeppa joint at the output shaft will operate at steeper angles and without ill effect the way a double cardan will. Also, factory gears spin much slower and so it'd be hard to get vibes with them.
 
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