Possible driveshaft or pinion angle issues

catbones2010

catbones2010

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Joined
Sep 14, 2022
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New York
Got a 2006 recently and while replacing some stock stuff, decided I'd go with 2" lift and 33 mud tires.

The problem I'm running into is that at 45mph I get my wheel shaking left to right like they aren't balanced. It ends at 50.

Wheels are at 28 psi cold per factory specs. Front axle angle is 7.3, driveshaft is 6.3, driver C is 7.1.

These tires are coming from my other TJ which had no vibration. Also the stock 30s that were on this TJ had no vibrations either.

I also noticed that adding more air to tires like 33psi moves the shakes to 50 and ends it at 55mph.

All steering stuff is new, nothing moves or wiggles that I can see, everything is tight and solid there.

I only feel the steering wobble, not death wobble either and I don't feel the vibrations in the seat.

So I'm wondering if anyone can help. I rear on here that maybe I should drop the cross member Trans down by 1/2 to correct the angles??
 
Id say if the wheel as you describe is shaking its not a drive line issue,its a wheel balance issue. Id start with swapping the rear tires up front and visa versa and see if that changes things. It dosent take much to make for some shaking.
 
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Jerry Bransford said:
A speed-sensitive shimmy/shake/vibration is tire or wheel related. Either an imperfect balance, even if done recently, a bad tire, or an out of balance or bent wheel.
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exactly whom I wanted to answer this post :) no offense to all others that will. I've been reading this forum and its articles for a couple years now just not registered or made post and you are very informative person when it comes to TJ. Thank you!

I'll go get my wheels checked for balancing, etc.. appreciate the response sir!
 
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Gilaguy23 said:
Id say if the wheel as you describe is shaking its not a drive line issue,its a wheel balance issue. Id start with swapping the rear tires up front and visa versa and see if that changes things. It dosent take much to make for some shaking.
Click to expand...

I agree that a good way to check this, and easy, is to switch the tires and wheels up. Track which one where, but put back to front same side, and see if it acts exactly the same, or completely different etc. Either way tire balancing is the most likely like others said, unfortunately sometimes you have to gather data so that you can direct the tire shop, balancing big tires for a lengthy amount of time is not conducive to a high margin, ha.
 
What lift? You may have caused another issue in the suspension when the lift was installed. I don't think a wheel is likely to become unbalanced by switching it onto another vehicle.

There is no such thing as a perfectly balanced wheel. I suspect some looseness in the suspension, or bushings not tightened properly is amplifying a slight (normally acceptable) wheel imbalance.

What happens if you swap the 30's back on? If you swap the 33's back to your other TJ I wonder if they would magically rebalance themselves

I think the likely variable that has changed is the lift kit.
 
And just to confirm, you said the "tires" came from your other TJ. Did you mean the wheels and tires from your other TJ or just the tires?
 
Vtx531 said:
What lift? You may have caused another issue in the suspension when the lift was installed. I don't think a wheel is likely to become unbalanced by switching it onto another vehicle.

There is no such thing as a perfectly balanced wheel. I suspect some looseness in the suspension, or bushings not tightened properly is amplifying a slight (normally acceptable) wheel imbalance.

What happens if you swap the 30's back on? If you swap the 33's back to your other TJ I wonder if they would magically rebalance themselves

I think the likely variable that has changed is the lift kit.
Click to expand...

That is what I thought but everything is as tight and as stable as it can be. Sat under there for a good amount of time having someoone turn the wheel all directions and nothing. Had it jacked up with suspension freely hanging and with weight, nothing, no movement. Installed new stabilizer just to make sure the Mopar original one wasn't doing a thing or weird thing. I know it has nothing to do with that and only masking the issue but heck, sometimes weird things happen when things are worn out. That didn't change.

I thought it would be suspension too but being able to air up the tire from 28psi to 33psi and the vibration move from 45-50 to 50-55, smells like tire. So unless when I swapped them one mounted on the axle wrong but I don't think so.

In terms of the other TJ, they were on there without any vibrations, that one has a 3" lift with 1.5" body lift and all sorts of stuff done to it. This 2006, got the tires after a 2" lift was put on, new springs and shocks. That is all. The 30s gave no vibration at all, before the lift and after the lift. Why more and more, its starting to sound like tires.

Now in terms of caster, angles, etc... I think I'd feel it in my seat and it would be at 80% of the time doing it, then just at 45-50 speeds and I wouldn't be able to put more air into the tire and move when the vibration happens, which is at higher speed. The only different thing I did with the tires when I moved it between the vehicles is I rotated them by putting left on right front and right on right front, same with the backs rather then normally going right front to right back and left front to left back or cross them (left front to rear right, right front to rear left).... maybe thats the issue. $24 for checking balance on the fronts isn't much either just to make sure and cross that possible balance issue.
 
catbones2010 said:
That is what I thought but everything is as tight and as stable as it can be. Sat under there for a good amount of time having someoone turn the wheel all directions and nothing. Had it jacked up with suspension freely hanging and with weight, nothing, no movement. Installed new stabilizer just to make sure the Mopar original one wasn't doing a thing or weird thing. I know it has nothing to do with that and only masking the issue but heck, sometimes weird things happen when things are worn out. That didn't change.

I thought it would be suspension too but being able to air up the tire from 28psi to 33psi and the vibration move from 45-50 to 50-55, smells like tire. So unless when I swapped them one mounted on the axle wrong but I don't think so.

In terms of the other TJ, they were on there without any vibrations, that one has a 3" lift with 1.5" body lift and all sorts of stuff done to it. This 2006, got the tires after a 2" lift was put on, new springs and shocks. That is all. The 30s gave no vibration at all, before the lift and after the lift. Why more and more, its starting to sound like tires.

Now in terms of caster, angles, etc... I think I'd feel it in my seat and it would be at 80% of the time doing it, then just at 45-50 speeds and I wouldn't be able to put more air into the tire and move when the vibration happens, which is at higher speed. The only different thing I did with the tires when I moved it between the vehicles is I rotated them by putting left on right front and right on right front, same with the backs rather then normally going right front to right back and left front to left back or cross them (left front to rear right, right front to rear left).... maybe thats the issue. $24 for checking balance on the fronts isn't much either just to make sure and cross that possible balance issue.
Click to expand...

Believe it or not, wheel balancing isn't an exact repeatable thing. Ex: if you balance a wheel on the machine, then take it off the machine, and put it back on the machine in a different position, it will almost certainly tell you to change the weights. So I can almost guarantee if you take them to get balanced, they will do it and tell you they were "off" but likely still have the same issues. This is why people end up going back to the same place multiple times and complaining they don't balance the wheels right and blame it on being a big tire or mud tire or whatever.

I think it would be more worthwhile (and free) to swap them back to the other TJ if you still have that ability. Take a ride with them and see what happens.
 
Vtx531 said:
And just to confirm, you said the "tires" came from your other TJ. Did you mean the wheels and tires from your other TJ or just the tires?
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Yes sorry, correct, wheels and tires, came from the other Jeep. No vibration on the other jeep but it also is built like lift and every other suspension thing improved. The other jeep has 149k and this 06 has 50k on it
 
Jerry Bransford said:
A speed-sensitive shimmy/shake/vibration is tire or wheel related. Either an imperfect balance, even if done recently, a bad tire, or an out of balance or bent wheel.
Click to expand...

Just for my info of driveshaft angles and such. What do you think of these, too much, too little, too much difference??

20220913_101017.jpg


20220913_100953.jpg


20220913_101100.jpg


20220913_101041.jpg
 
catbones2010 said:
Just for my info of driveshaft angles and such. What do you think of these, too much, too little, too much difference??

View attachment 359444

View attachment 359445

View attachment 359446

View attachment 359448
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You only need to insure your rear pinion angle is the same as the driveshaft's. That the pinion shaft points directly at the DC joint directly up the driveshaft. It absolutely cannot point above the driveshaft though it can point as much 1/2 to 1 degree below it.

Double_Cardan_driveshaft_large.png
 
Jerry Bransford said:
You only need to insure your rear pinion angle is the same as the driveshaft's. That the pinion shaft points directly at the DC joint directly up the driveshaft. It absolutely cannot point above the driveshaft though it can point as much 1/2 to 1 degree below it.

View attachment 359493
Click to expand...

What about the front angles, driveshaft, axles, etc... those photos were from the front. :)
 
So I'm starting to think I should try to either go for 7 degrees or 6 degrees on the driver C, maybe first 7, then 6.5, then 6 caster and see. My 7.7 degrees of caster might be whats giving me that slight vibration. This is after swapping the tires with front and back. Read couple posts where caster and driveshaft angles in my specs was just slightly too much. However, if I change the degree on the C to 6 degrees, that means my driveshaft and pumpkin of the front axle will end up being like 7 and 8 degrees, wont it? but it doesn't matter if its 7 and 8, as long as the difference is within 2, correct?
 
catbones2010 said:
What about the front angles, driveshaft, axles, etc... those photos were from the front. :)
Click to expand...
Stop worrying about the exact angle numbers, they vary depending on wheelbase, engine type, and transmission type. All you need to worry about is if the pinion angle is the same as the driveshaft. If they are the same it will be correct for your DC driveshaft.
 
Jerry Bransford said:
Stop worrying about the exact angle numbers, they vary depending on wheelbase, engine type, and transmission type. All you need to worry about is if the pinion angle is the same as the driveshaft. If they are the same it will be correct for your DC driveshaft.
Click to expand...

Ok so from that, in my case from the pictures, I got 6.3 angle on the driveshaft and 7.5 on the circle thingies on the pumpkin / axle... meaning I'd need to adjust it, so that 6.3 and 7.5 are much closer to each other in number, if not even equal, correct?? sorry, just a dumbass in all this axle and driveshaft stuff. Which would also make driver C go from 7.7 to lower number.
 
Jerry Bransford said:
When these two measurements give the same numbers life will be good.
View attachment 359590

View attachment 359591
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Ok so at my front, I've got 7.5 so I need to go and see what my angle is at the driveshaft area near the transfer case, correct? based on the photos you sent me looks like the second picture shows measuring it near the transfer case end of the driveshaft
 
Jerry Bransford said:
The driveshaft angle is the same no matter if it's measured from the front or rear.
Click to expand...

I see, ok so I got to equal out the 6.3 with the 7.5 then but rotating the axle upwards wouldn't it increase the 7.5 rather then reduce it to get it closer to the 6.3 measurement. Like if I was trying to achieve 7 from 6.3, doing so would increase 7.5 to 8 for example. Maybe I'm wrong.

Now that I think about it, maybe I should do the opposite to equal those. For my understanding, the yoke/axle doesn't have to face the angle of the driveshaft or does it?

Which one am I looking for correctly??

1. https://www.awesomescreenshot.com/image/32451147?key=083bd7c2a2db82a608db012baecfb017

2. https://www.awesomescreenshot.com/image/32451161?key=4b91ff7be68c185eeb44fdb49433aa09
 
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