Jeep Re-gear Vibrations

[catbones2010]

Well actually I was thinking about calling Tom Woods as I was typing that-

It’s a pretty fresh build so I’m just now sorting out everything and for a while I thought I was going to get it with pinion angle but it’s not gonna happen I think- I’ve got it coming in at 62 plus but that’s the best I can do-

I have another shaft in good condition for a Rubicon I’m going to put on it this evening if the rain lets me back my LJR with the top off out- I’m going to give that a spin without a lot expectation- if no joy the go CV. It has adjustable arms so I am prepared

Well keep me posted on this please, if you can. I was thinking, about doing SYE + CV shaft, but with it being LJ and 2" didnt think I'd need it. Plus, taking the front driveshaft out and the vibes gone, exactly what made me thing that front might be not balanced right or at least its balanced till 3000rpms, while now I'm doing more like 3500rpms for same speed.

 

[AndyG]

A buddy got his hands on one that was stock the other day and you know we really forget just how good these things are until we start changing things- You just can’t change one thing without changing a lot of things is a really true statement.

Above is his new one which is identical to what I started with-

 

[AndyG]

Well keep me posted on this please, if you can. I was thinking, about doing SYE + CV shaft, but with it being LJ and 2" didnt think I'd need it. Plus, taking the front driveshaft out and the vibes gone, exactly what made me thing that front might be not balanced right or at least its balanced till 3000rpms, while now I'm doing more like 3500rpms for same speed.

Sure will.

 

[catbones2010]

Sure will.

btw, just for my fyi... before putting SYE and CV shafts in the rear, do you know if your front was doing the vibes or was it your rear? or are you saying the rear was fighting the front CV driveshaft?

 

[AndyG]

btw, just for my fyi... before putting SYE and CV shafts in the rear, do you know if your front was doing the vibes or was it your rear? or are you saying the rear was fighting the front CV driveshaft?

That’s where it get’s tricky- there can be a harmonic between the two, transference from front to rear or rear to front or both, a trans mount too weak to handle the dynamics, u-joint issues, bad harmonic balancers and more.

I don’t think any of us can just put a finger on it everytime so we all end up dissecting the problem the best we can.

 

[catbones2010]

That’s where it get’s tricky- there can be a harmonic between the two, transference from front to rear or rear to front or both, a trans mount too weak to handle the dynamics, u-joint issues, bad harmonic balancers and more.

I don’t think any of us can just put a finger on it everytime so we all end up dissecting the problem the best we can.

I hear ya! Well, I will start with the front DS replacement and well balanced to be known for sure, if that doesn't change anything I might look into trans mount and rear CV.

I know my 97 TJ, I put 410 in it, cv new driveshafts, SYE, etc as I was building it and no vibes at all. 4.10 also spin below 2715rpms and 5.13 call for about 3400rpm. Almost 700rpm difference. Few articles and Spicer states their DS stock max are balanced for 3000rpms. Why I'm thinking I might need new, thicker, stronger, balanced front and see how that does. If it moves the vibes higher in speed on the thruway, I'll be happy as I said before I don't go above 65mph, other then that one time.

 

[AndyG]

I hear ya! Well, I will start with the front DS replacement and well balanced to be known for sure, if that doesn't change anything I might look into trans mount and rear CV.

I know my 97 TJ, I put 410 in it, new driveshafts, etc as I was building it and no vibes at all. 4.10 also spin below 2715rpms and 5.13 call for about 3400rpm. Almost 700rpm difference. Few articles and Spicer states their DS stock max are balanced for 3000rpms. Why I'm thinking I might need new, thicker, stronger, balanced front and see how that does. If it moves the vibes higher in speed on the thruway, I'll be happy as I said before I don't go above 65mph, other then that one time.

I wonder if there would be a way to put something like an active balancer on a harmonic balancer- kinda like a centramatic-


I think it’s been talked about

 

[catbones2010]

I wonder if there would be a way to put something like an active balancer on a harmonic balancer- kinda like a centramatic-


I think it’s been talked about

I came across these but other than one video, which in comments the guy states it fixed his vibes on his truck, nothing else I was able to find about them or success stories; https://balancemasters.company.site/Driveshafts-c126873596

 

[MightyJoe]

I hear ya! Well, I will start with the front DS replacement and well balanced to be known for sure, if that doesn't change anything I might look into trans mount and rear CV.

I know my 97 TJ, I put 410 in it, cv new driveshafts, SYE, etc as I was building it and no vibes at all. 4.10 also spin below 2715rpms and 5.13 call for about 3400rpm. Almost 700rpm difference. Few articles and Spicer states their DS stock max are balanced for 3000rpms. Why I'm thinking I might need new, thicker, stronger, balanced front and see how that does. If it moves the vibes higher in speed on the thruway, I'll be happy as I said before I don't go above 65mph, other then that one time.

Will be curious to how it turns out. I have 4 regeared rigs atm, 4.88, 4.88, 5.29, 5.38 and none of them had vibes after a regear.

 

[catbones2010]

Will be curious to how it turns out. I have 4 regeared rigs atm, 4.88, 4.88, 5.29, 5.38 and none of them had vibes after a regear.

Lucky! stock shafts still?

 

[catbones2010]

Will be curious to how it turns out. I have 4 regeared rigs atm, 4.88, 4.88, 5.29, 5.38 and none of them had vibes after a regear.

Like I mentioned the 97 TJ has 4" of lift, 33's, 4.10s, and no vibes, but has the SYE and Adams both front end rear. I didn't drive it at all until all that was done. No vibes on the truth way like the LJ has, but LJ has 33's, 5.13s and 2" lift but also stock driveshafts.

 

[starkey480]

Many people here have driven themselves mad trying to solve the vibes. I did a hub kit up front for my front driveshaft vibes and can drive as fast as I want now with zero vibes. Haven’t looked back since.

 

[catbones2010]

Many people here have driven themselves mad trying to solve the vibes. I did a hub kit up front for my front driveshaft vibes and can drive as fast as I want now with zero vibes. Haven’t looked back since.

Yeah but why does it happen. Some solved it and some didn't. Some didn't even get it. That makes no sense. Higher hears is fine, lower its not. Hubs sure I know that's an option but than you Frankenstein your jeep I feel like because now you got thus big chunk of weight you carry for absolutely nothing, transfer case. No on the fly 4x4 either. Kinda dumb, sad solution.

 

[starkey480]

Yeah but why does it happen. Some solved it and some didn't. Some didn't even get it. That makes no sense. Higher hears is fine, lower its not. Hubs sure I know that's an option but than you Frankenstein your jeep I feel like because now you got thus big chunk of weight you carry for absolutely nothing, transfer case. No on the fly 4x4 either. Kinda dumb, sad solution.

Higher numerical gears mean higher driveshaft RPM for a given speed. So any imbalance in the front driveshaft will be amplified the deeper the gearing. I’ve seen people battle vibes for years and spend enough money for 2 hub kits and still not solve it. Choose your poison, get out and unlock the hubs for 4X4 or have a speed limit of 60mph. This is of course assuming you’ve covered the basics like front driveshaft balance, pinion angle, and making sure the joints are good.

 

[catbones2010]

Higher numerical gears mean higher driveshaft RPM for a given speed. So any imbalance in the front driveshaft will be amplified the deeper the gearing. I’ve seen people battle vibes for years and spend enough money for 2 hub kits and still not solve it. Choose your poison, get out and unlock the hubs for 4X4 or have a speed limit of 60mph. This is of course assuming you’ve covered the basics like front driveshaft balance, pinion angle, and making sure the joints are good.

Well I'm at the start, not the finish line yet I will replace both driveshafts starting with the front since if I remove the front all is good. So either the front is fighting the read driveshaft or front isn't balanced, or maybe the rear isnt balanced well and its fighting the front. I guess maybe I should drop the front and see how that goes. However, if I disconnected the front driveshaft from the axle and vibes went away, no need to test with rear out because with it without front is fine. Ugh! I guess I can ask Tom Wood or local driveshaft to balance it at 3600 rpms and see how that rides. I'll be okay with vibes starting at 75 or something close to that but I do need 65mph lol

 

[catbones2010]

If you guys ever watch the video that Shawn from Tom Woods made about driveshafts and he then shows the misbalanced driveshaft on his balancer, when he turns it up to 3000rpms at the very end, that is what mine sounds like. Is that what people are referring to with the vibrations, harmonic noise, etc.. or is it different? for reference.

 

[deadbeat son]

I guess maybe I should drop the front and see how that goes. However, if I disconnected the front driveshaft from the axle and vibes went away, no need to test with rear out because with it without front is fine. Ugh!

It's worth the effort to drop the rear and drive with front only, IMO. That will help you narrow down whether the problem is truly the front shaft or if it's an imbalance between the two.

 

[Rickyd]

A couple thoughts here besides balance or replace. Though that is a good idea.

-How much play is in the front transfercase output? Pinion?

-have you tried rotating the pinion both ways to see if the vibration disappears?

 

[catbones2010]

It's worth the effort to drop the rear and drive with front only, IMO. That will help you narrow down whether the problem is truly the front shaft or if it's an imbalance between the two.

Yes sure is, just did that and while I'm getting a little bit of vibration, nothing like when they are both in. So that is interesting. Now, I've put both back in and the vibes are back. I think maybe both are unbalanced fighting each other. Another thought and something I noticed, while trying to move the rear driveshaft back and forth to see if there is any play in it (slight play in ujoint but maybe thats normal, like up and down), I also noticed that I can jiggle / move slightly the transmission within its mount. Not sure thats normal? should I not be able to move it sideways?

 

[catbones2010]

A couple thoughts here besides balance or replace. Though that is a good idea.

-How much play is in the front transfercase output? Pinion?

-have you tried rotating the pinion both ways to see if the vibration disappears?

-How much play is in the front transfercase output? Pinion?
No play in the pinion, I think I see a little bit of play in the front output shaft at the transfercase, but very very little if anything

-have you tried rotating the pinion both ways to see if the vibration disappears?
Yes, did that as well.

I've noticed that I got slight play in the rear ujoint, but very very little if any. However, I can also jiggle or move the transfercase / transmission a bit left/right looking at the transmission mount/rubber. Not sure there should be any play within that. Got to say I also got quite a bit of drone sound at a stop idling in the cab from the engine, maybe transmission mount rubber is done or engine mounts too but that's not related, well at least not engine mounts, transmission mount maybe. I don't know I guess how much play there is with a new transmission mount, I'm guessing its not super stiff either.