Re-geared, now I have a vibration above 50 mph

Sharing my experience w mine as well, seems to be inline w what has been described on this post.

Mine did the same thing, after I regeared from 4.56 to 4.88 w yukons. Dana 44 axles, np241 and nv3550 tranny, Jeep west did the gears, then they changed bearings n u joints in the front as well as the DS, that helped a lot but still there around 60mph, rearview mirror tells u cant see all that good thanks to the vibration.

I read somewhere the tc output bearings to the shafts may need replaced w something that handles higher rpms better but i have not been able to find dose or if is a real thing.

Anyways, if anyone has more info let us know!


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This might simply be a Jeep thing :risas3:

You guys should read these threads.

https://www.jlwranglerforums.com/forum/threads/rubicon-2-door-drive-line-vibration.13529/

https://www.jlwranglerforums.com/forum/threads/thrumming-noise-at-highway-speeds-63-67ish.10189/


On a more serious note, I had a great chat with Blaine today. He said my ideas and thinking reg the balancer/skid has merit and is worth pursuing. I'll post a proper update on my conversation with him after I talk to Dave in more detail.
 
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Fouledplugs said:
Could be way off here, but trying to keep it simple. (I have a theory to go off here) Did you go with Dana Spicer rings and pinions?
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No, I did not. The rear got Motive gears with a thick cut R&P so I could keep my Traklock carrier. Front got Motive as well, then G2 after suspecting the setup was wrong.
 
bobthetj03 said:
No, I did not. The rear got Motive gears with a thick cut R&P so I could keep my Traklock carrier. Front got Motive as well, then G2 after suspecting the setup was wrong.
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So only after swapping in the gears did you get the vibes, correct?

It didn't vibe with Dana gears in it. And now after swapping to imported Chinese/Korean gears its got vibes...

I understand there are more parameters (higher driveshaft RPM’s being one of them) and it’s probably impossible to narrow down the issue to one single part without a lot of trialxand error, not to mention money, but it still begs the question...

Why not go with genuine Dana gears? The Dana track lock would be to be removed even with Dana gears? They are available and competitively priced with all the knock off crap that comes from China/Korea/India....

Just trying to keep it simple and outside the box a little.

It’s odd to me that we(the forum) love the Dana axles, parts that are made in the USA, and yet when it comes to swapping ratios, everyone jumps on the imported gears that are obviously not manufactured to the same standards as the OEM parts.
 
I will admit, it’s hard to find on Dana’s websites if they make their R&P’s in the USA or not.

I’m betting someone will just throw it out there that “they are PROBABLY made in the same overseas manufacturing plants” but without any real concrete evidence. (That’s my favorite one)
 
Fouledplugs said:
So only after swapping in the gears did you get the vibes, correct?

It didn't vibe with Dana gears in it. And now after swapping to imported Chinese/Korean gears its got vibes...

I understand there are more parameters (higher driveshaft RPM’s being one of them) and it’s probably impossible to narrow down the issue to one single part without a lot of trialxand error, not to mention money, but it still begs the question...

Why not go with genuine Dana gears? They are available and competitively priced with all the knock off crap that comes from China/Korea/India....

Just trying to keep it simple and outside the box a little.

It’s odd to me that we(the forum) love the Dana axles, parts that are made in the USA, and yet when it comes to swapping ratios, everyone jumps on the imported gears that are obviously not manufactured to the same standards as the OEM parts.
Click to expand...

I wanted to keep the factory traclock in the Dana 44, so I needed a thick cut ring gear.
 
@bobthetj03

If you still have your front driveshaft out, run up to highway speeds in 4 wheel drive and see if the vibration is worse than in 2wd. If the vibrations are worse, you have a huge clue to go off of. I can't imagine why they would get worse, but just a test to try I guess.

I'm really out of ideas at this point so I'm just throwing stuff out there and hoping something happens.
 
bobthetj03 said:
I wanted to keep the factory traclock in the Dana 44, so I needed a thick cut ring gear.
Click to expand...
Interesting. Makes me wonder what non thick gears would do vibe wise. As well as how domestic gears would play when it comes to vibes.

I may have missed it. But did you paint the gears with marking compound and spin it by hand since breaking them in? How was the mesh pattern? Heel? Toe? Centered?

Example of a toe heavy mesh pattern which needs to be adjusted to get centered:
A4E901C1-7AB0-40DC-B578-2AFD6C226656.jpeg
 
jodomcfrodo said:
@bobthetj03

If you still have your front driveshaft out, run up to highway speeds in 4 wheel drive and see if the vibration is worse than in 2wd. If the vibrations are worse, you have a huge clue to go off of. I can't imagine why they would get worse, but just a test to try I guess.

I'm really out of ideas at this point so I'm just throwing stuff out there and hoping something happens.
Click to expand...

Did that, up to 65mph. No change.
 
I
bobthetj03 said:
Did that, up to 65mph. No change.
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Have to admit I had a sigh of relief when I didn't hear or feel a vibration once I finally put my top back on. I haven't had it on since my 4.88 regear at the beginning of summer.
 
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Fouledplugs said:
Interesting. Makes me wonder what non thick gears would do vibe wise. As well as how domestic gears would play when it comes to vibes.

I may have missed it. But did you paint the gears with marking compound and spin it by hand since breaking them in? How was the mesh pattern? Heel? Toe? Centered?

Example of a toe heavy mesh pattern which needs to be adjusted to get centered:
View attachment 62980
Click to expand...

Did this recently, after discovering a rear diff cover leak, so I marked and spun a pattern. I think I posted pics earlier in this thread. @Rob5589 commented that my pinion depth was deep. I agreed.

A re-re gear may be in my future for the rear diff. I think I want to steer away from a thick cut gear and get a Detroit Trutrac
 
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bobthetj03 said:
Did this recently, after discovering a rear diff cover leak, so I marked and spun a pattern. I think I posted pics earlier in this thread. @Rob5589 commented that my pinion depth was deep. I agreed.

A re-re gear may be in my future for the rear diff. I think I want to steer away from a thick cut gear and get a Detroit Trutrac
Click to expand...
Sounds like a couple of things to play with and change if you wanted to and you just might get rid of the vibes. I'm confident it can be fixed as the only change you made was re-gearing when you got vibes.
 
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Fouledplugs said:
Sounds like a couple of things to play with and change if you wanted to and you just might get rid of the vibes. I'm confident it can be fixed as the only change you made was re-gearing when you got vibes.
Click to expand...

Yes, I really am kicking myself concentrating on the front diff, when I now believe it is the rear causing havoc! Revolution is now coming out with a gear set that doesn't need a break in period. Thoughts?
 
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bobthetj03 said:
Yes, I really am kicking myself concentrating on the front diff, when I now believe it is the rear causing havoc! Revolution is now coming out with a gear set that doesn't need a break in period. Thoughts?
Click to expand...

I’ll be buying them this week. It’s a treatment on their regular gears from my understanding.
 
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Have you checked your harmonic balancer on the engine? They do wear out...You've been through SO much in the driveline that I wonder if its not somewhere else, especially since you've said you still have vibs without the Front DS.

They are cheap and should be relatively easy to replace...might be a worthwile experiment.
 
Ranger_b0b said:
Have you checked your harmonic balancer on the engine? They do wear out...You've been through SO much in the driveline that I wonder if its not somewhere else, especially since you've said you still have vibs without the Front DS.

They are cheap and should be relatively easy to replace...might be a worthwile experiment.
Click to expand...

Not a bad idea. Jeep's got 164K on it, so it's not a far stretch that the balancer has weakened in its performance.
 
So, in addition to changing the harmonic balancer as @Ranger_bOb has suggested, I have a new Spicer yoke for the rear diff. I also have new yokes for the tc input and output given to me by Tom Woods. I'll probably do the rear yoke first, then work my way forward if I get no positive results.
Another thought concerning my tc skid. I recently swapped out the factory shovel for a heavier, thicker Barnes skid. This skid raised the drive train up 1". This change made no noticeable difference in the vibe department. I was hopeful it might change the harmonic frequency in my favor, but alas, it did naughteen!
Thinking about ds operating angles got me wondering if I need to go the other direction? In order to do this I'll need to drop the skid 2". that is a lot, but I think it needs to be part of the experiment to see if operating angles are part of the equation. It's either do that or lower the suspension, neither of which I want to do.
 
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