Re-gear vibe eliminated

[AndyG]

I have 4:56 gears with 33” tires on my ‘03 Rubi

After the regear , which I have now nearly worked through in therapy , it had a pulsing vibe at 67 mph and up.

At the time , there were a number of deep and complex regear vibe threads , and my whole regear experience was so dramatic, it seemed to chase the vibe was a rabbit hole I didn’t want to go down.

Talking to a friend who is pretty common sense with mechanical things , he said you know , if you pull the shaft and it fixes it , you really need to get the shaft looked at.


Either it got worse or I noticed it more lately , feeling some buzz slightly at 40 and over , so I pulled the front shaft.

Smooth as glass , at all speeds, I mean a different Jeep. Keep in mind it is soundproofed , has a hard top, all terrain tires , the top of the line spicer u joints , and is fairly car like with 50,000 miles .

So I took it to the drive shaft shop yesterday to have it checked ...they called today , said it was out of balance , welded decent size weights to it on both ends.

I put it on tonight ...that fixed it.

Remember , a vibrating shaft can be seen at speed on a lift ...and shops need to run the shaft beyond the speed you plan to drive .

I know this isn’t the universal solution , but it was for me ....and I can’t be the only guy ...drive shaft balance is critical, and we all have 2 spinning if the hubs are stock.

 

[Chris]

@psrivats, you might enjoy reading this.

@toximus bought my TJ from me that had this same pulsating vibe after the re-gear. He solved it with manual locking front hubs, but I'm not sure he ever tried something like this with the front shaft. Might be an interesting experiment if you ever get bored @toximus.

@bobthetj03, we still have hope for you!

 

[AndyG]

@psrivats, you might enjoy reading this.

@toximus bought my TJ from me that had this same pulsating vibe after the re-gear. He solved it with manual locking front hubs, but I'm not sure he ever tried something like this with the front shaft. Might be an interesting experiment if you ever get bored @toximus.

@bobthetj03, we still have hope for you!

There is actually a you tube video where a guy does it on the vehicle with hose clamps ...lot of trial and error .

Shafts don’t cause all vibes , but any unbalanced shaft is sure to be suspect .
Thanks for passing it along Chris ...good job as usual.

 

[astjp2]

so will a worn ball on the double cardan

 

[Vinman]

There is actually a you tube video where a guy does it on the vehicle with hose clamps ...lot of trial and error .

Shafts don’t cause all vibes , but any unbalanced shaft is sure to be suspect .
Thanks for passing it along Chris ...good job as usual.

As hack as balancing with hose clamps sounds that method is actually documented in the factory service manual as a method of diagnosing an out of balance driveshaft.

 

[Steel City 06]

I’ve had a vibration for a while now that is solved by removing the front shaft. Put a new Tom Wood shaft in with no change. Adjusting pinion angle to perfectly in-line doesn’t do anything (except make steering sketchy). I’m tempted to try the Balance Masters driveshaft balancers, especially after seeing what the Centramatics do with tire balance

http://www.balancemasters.com/driveshafts.html

 

[Brianj5600]

I am a fan of air soft balance tire beads because it is simple, reliable and inexpensive. I don't doubt that driveshaft version works, but if you have to put one on each end, it could be susceptible to trail damage.

 

[AndyG]

so will a worn ball on the double cardan

I would think a worn double cardan would really act up...good post.

 

[Steel City 06]

According to Balance Masters, you can only use the balancer at one end of each shaft. Putting them at opposite ends will cause them to fight each other. So first I would try the Double Cardan (DC) end and only move to the pinion end if the DC end balancer does not do much.

 

[AndyG]

I’ve had a vibration for a while now that is solved by removing the front shaft. Put a new Tom Wood shaft in with no change. Adjusting pinion angle to perfectly in-line doesn’t do anything (except make steering sketchy). I’m tempted to try the Balance Masters driveshaft balancers, especially after seeing what the Centramatics do with tire balance

http://www.balancemasters.com/driveshafts.html

Get the thing on the lift and get it up to speed and see what the shaft is doing... If you don't see weights on one it's not been balanced.

 

[AndyG]

As hack as balancing with hose clamps sounds that method is actually documented in the factory service manual as a method of diagnosing an out of balance driveshaft.

You know really it's so pretty cool idea... You actually have a lot of flexibility with it if you figure out the method.

I bet there are more of these that are front drive shaft related than people think... I wonder if there are different methods for balancing shafts in shops.

 

[AndyG]

I'm going to say this about balancing... If they are not running the shaft up to speed... They aren't catching the full range of possibility. If regearing the vehicle increases the shaft speed.. it seems to make sense that it would have to be balance to something like the RPM for 75 miles per hour to duplicate 65 miles per hour rpm ... I may be a hundred percent wrong on that so definitely take it with a grain of salt... Whatever taking it with a grain of salt means.

 

[freedom_in_4low]

I had new vibes after my regear as well. At the time of the regear, I had no vibes, a MML, and a short (about 5/8)" t case drop.

Then afterward, I had vibes starting around 60. Added t-case drop to about 1.25" and got it tolerable but still there. Decided it was finally time for an SYE, and I took the shotgun approach with a JB super short.

While I had the transfer case and front driveshaft out I found the centering ball was loose. So I replaced it, as well as all three u joints.

I just put my new Tom Wood rear shaft in last night and will have my first test drive later today. I may have dumped $1200+ into an SYE because of a $70 centering ball, but if the vibes are gone, I don't even care.

 

[AndyG]

I had new vibes after my regear as well. At the time of the regear, I had no vibes, a MML, and a short (about 5/8)" t case drop.

Then afterward, I had vibes starting around 60. Added t-case drop to about 1.25" and got it tolerable but still there. Decided it was finally time for an SYE, and I took the shotgun approach with a JB super short.

While I had the transfer case and front driveshaft out I found the centering ball was loose. So I replaced it, as well as all three u joints.

I just put my new Tom Wood rear shaft in last night and will have my first test drive later today. I may have dumped $1200+ into an SYE because of a $70 centering ball, but if the vibes are gone, I don't even care.

Well you upgraded everything and still got out cheaper than selective hubs... And I know exactly where you're coming from... The benefit of good gearing and the enjoyment of a really smooth Jeep make it easy to commit a little bit more money .... I also have thrown some money at things , and that's a little bit what is annoying about the whole deal... We all end up doing some guess work.

I can really relate... It's just so nice to have the problem solved.

 

[bobthetj03]

It's good to hear some good news in the vibes front. Sadly, I'm still chasing mine. My MML helped a lot, so I feel convinced that my vibes problem is driveshaft operating angle related. Those balancing rings are intriguing. Having tried 3 different front shafts and 2 different rear shafts, and then shipping the front shaft to Tom Woods for inspection/balance, I just can't imagine it is out of balance, but stranger things have happened.

 

[AndyG]

It's good to hear some good news in the vibes front. Sadly, I'm still chasing mine. My MML helped a lot, so I feel convinced that my vibes problem is driveshaft operating angle related. Those balancing rings are intriguing. Having tried 3 different front shafts and 2 different rear shafts, and then shipping the front shaft to Tom Woods for inspection/balance, I just can't imagine it is out of balance, but stranger things have happened.

Has anyone ever put that jeep on the lift and got it up to speed? I'm just wondering if these things are being balanced to the RPM they need to be balanced to. I know that's like saying I know something that all these driveshaft people don't know... But you can tell real quick if a shaft is not balanced when you see one ran on lift .

I may be wrong but I think you can distinguish that from something going on in the differential.... In some cases at least.

 

[bobthetj03]

Has anyone ever put that jeep on the lift and got it up to speed? I'm just wondering if these things are being balanced to the RPM they need to be balanced to. I know that's like saying I know something that all these driveshaft people don't know... But you can tell real quick if a shaft is not balanced when you see one ran on lift .

I may be wrong but I think you can distinguish that from something going on in the differential.... In some cases at least.

Haven't tried it up to speed since I'm solo most times, but I did put it on jack stands, run it at idle in 5th gear and couldn't see anything out of the ordinary. I also measured runout of all 4 yokes and the driveshaft tubes, front and rear.

A imperfectly balanced drive shaft still doesn't explain why lowering the t-case skid 1" inch improved the vibes quite a bit. I'm still scratching my head on this one, and am currently experimenting more with the t-case skid. I have it dropped 5/16" with washers and plan to readjust the rear pinion and see what I net. Fyi, adding the MML basically netted me the same result as dropping the t-case skid, but didn't totally eliminate the vibes above 63mph.

 

[AndyG]

Haven't tried it up to speed since I'm solo most times, but I did put it on jack stands, run it at idle in 5th gear and couldn't see anything out of the ordinary. I also measured runout of all 4 yokes and the driveshaft tubes, front and rear.
View attachment 141512View attachment 141513View attachment 141514
A imperfectly balanced drive shaft still doesn't explain why lowering the t-case skid 1" inch improved the vibes quite a bit. I'm still scratching my head on this one, and am currently experimenting more with the t-case skid. I have it dropped 5/16" with washers and plan to readjust the rear pinion and see what I net. Fyi, adding the MML basically netted me the same result as dropping the t-case skid, but didn't totally eliminate the vibes above 63mph.

Yes it's hard to isolate or even consider isolating one thing when it could be one or several things going on anyway... I hate that all this is so elusive... And I hate that it's over my head but it doesn't take much for things to be over my head.

 

[eastbloc]

Damn regear vibes, we need to make an encyclopedia on this.

I was suspecting a front driveshaft on mine. After taking it off, vibes shifted to different speeds which I didn't find out till later on the highway. So surely it was a driveshaft I thought in my head.

In reality it was a combination of two things: issue with regear job, things came lose twice inside the axle housing. And front passenger tire, out of the blue, for what ever mysterious reason became extremely unbalanced.

 

[AndyG]

Damn regear vibes, we need to make an encyclopedia on this.

I was suspecting a front driveshaft on mine. After taking it off, vibes shifted to different speeds which I didn't find out till later on the highway. So surely it was a driveshaft I thought in my head.

In reality it was a combination of two things: issue with regear job, things came lose twice inside the axle housing. And front passenger tire, out of the blue, for what ever mysterious reason became extremely unbalanced.

Good post... I think if you persist on these things you're going to get to the bottom of it often.

I would love to solve this for anybody.. and the whole reason I didn't even get mine corrected sooner is the the entire issue was so complex I didn't even try too hard...not a good formula.

I definitely want to cast down the thought that the average Joe can get these things figured out because of some cases he can.