Vibration solutions

[mdepenning]

Get a 3 and 1/2 lift on my 2003 Wrangler. X. Had major vibration and so drop the transfer case. Had to take it down to almost an inch and 3/4. Nearly all the vibration is gone but there still is some. Hate to drop it any further. What else should I be looking for? Really appreciate your help or suggestions.

 

[Duck Doctor]

Tcase drop is not an ideal solution. If you want to permanently correct the vibration issue then an SYE, adjustable upper rear control arms, and a DC driveshaft are necessary. Then you can remove the tcase drop so the skid isn't hanging so low.

 

[GregBelleville]

Another option to reduce the vibes would be to install a motor mount lift.

A 1"motor mount lift may allow you to reduce the TC drop a bit until you're ready to do the SYE, DC driveshaft and adjustable control arms.

 

[The4bangertj]

If it is still drive line vibrations you can see how the angles are. A stock single u joint shaft needs the yoke ends to be parallel so if you added the motor lift you will need to adjust le pinion angle to match which at least both rear control arms.
The best solution is an sye, dc driveshaft (Tom woods is mine and many others choice driveshaft maker) and rear upper and lower control arms for pinion angle.

I also believe that for a single joint like stock the shaft should be as flat as possible and once you get close to 15 degrees of drive shaft angle off the parallel plane of the yoke, you really need to do a sye and dc shaft as 15 degrees on the stock shaft will always have some vibration no matter how perfectly the 2 yoke ends are parallel to each other.

 

[mrblaine]

Tcase drop is not an ideal solution. If you want to permanently correct the vibration issue then an SYE, adjustable upper rear control arms, and a DC driveshaft are necessary. Then you can remove the tcase drop so the skid isn't hanging so low.

Why uppers?

 

[OldBuzzard]

Why uppers?

This would be a good time to mention this thread https://wranglertjforum.com/threads/questions-on-partial-rubicon-tummy-tuck.78917/
in which I say "uppers only" and Mr. Blaine corrects me with a clear explanation of why uppers AND lowers are needed, or at a minimum just lowers (thanks, Blaine).

 

[Duck Doctor]

Why uppers?

How about uppers and lowers.

 

[The4bangertj]

Good read. I also said just uppers and have just uppers in my jeep. It has worked but I can see how more lift and more tuck would cause even more tilt to the pinion and making the wheelbase further than acceptable, thus needing both upper and lowers. Apparently it’s not posted enough (or the bad info is just posted more) and I’m not looking enough, because I still had the wrong knowledge.

 

[mdepenning]

Another option to reduce the vibes would be to install a motor mount lift.

A 1"motor mount lift may allow you to reduce the TC drop a bit until you're ready to do the SYE, DC driveshaft and adjustable control arms.

Sorry to sound so ignorant, but sometimes I am. Only way to learn. What are the adjustable control arms?

 

[GregBelleville]

Control arms connect the frame to the axles, their purpose is to hold the axles in place front to back, setting your wheelbase. Additionally, control arms set the pinion angle for each axle, which is the angles of your driveshafts. There is an upper and lower control arm at each corner, for a total of 8.

Adjustable control arms can be lengthened to adjust wheelbase and pinion angles after a suspension lift has been installed.

 

[mrblaine]

Control arms connect the frame to the axles, their purpose is to hold the axles in place front to back, setting your wheelbase. Additionally, control arms set the pinion angle for each axle, which is the angles of your driveshafts. There is an upper and lower control arm at each corner, for a total of 8.

Adjustable control arms can be lengthened to adjust wheelbase and pinion angles after a suspension lift has been installed.

There are actually 10 control arms, we just call 2 of them by different names.

 

[GregBelleville]

There are actually 10 control arms, we just call 2 of them by different names.

Track bars I'm assuming?

 

[ColoJeep]

Track bars I'm assuming?

Yes , Or we could go down the road referring to them as panhard rods . All this seems silly though .

 

[mdepenning]

Control arms connect the frame to the axles, their purpose is to hold the axles in place front to back, setting your wheelbase. Additionally, control arms set the pinion angle for each axle, which is the angles of your driveshafts. There is an upper and lower control arm at each corner, for a total of 8.

Adjustable control arms can be lengthened to adjust wheelbase and pinion angles after a suspension lift has been installed.

Thank you. Makes sense

 

[mrblaine]

Yes , Or we could go down the road referring to them as panhard rods . All this seems silly though .

Except for the fact that they are control arms.

 

[mdepenning]

Tcase drop is not an ideal solution. If you want to permanently correct the vibration issue then an SYE, adjustable upper rear control arms, and a DC driveshaft are necessary. Then you can remove the tcase drop so the skid isn't hanging so low.

I know this is going to sound like a crazy question, but if I only use an sye and DC drive shaft without installing adjustable control arms, will that work? I've had so much rust issues under this Jeep that it's hard to remove bolts.

 

[mdepenning]

If it is still drive line vibrations you can see how the angles are. A stock single u joint shaft needs the yoke ends to be parallel so if you added the motor lift you will need to adjust le pinion angle to match which at least both rear control arms.
The best solution is an sye, dc driveshaft (Tom woods is mine and many others choice driveshaft maker) and rear upper and lower control arms for pinion angle.

I also believe that for a single joint like stock the shaft should be as flat as possible and once you get close to 15 degrees of drive shaft angle off the parallel plane of the yoke, you really need to do a sye and dc shaft as 15 degrees on the stock shaft will always have some vibration no matter how perfectly the 2 yoke ends are parallel to each other.

View attachment 558960

If I only do a sye and DC shaft, would it work without installing adjustable, rear, upper and lower control arms? I have a lot of rust issues and troubles removing bolts on this Jeep. I'm assuming the drive shafts would not be a real big issue to replace, but the control arms may be a much bigger project? That is why I am asking this. Thanks for the great information you've already given.

 

[macleanflood]

I did just that on my 97. Clutch was shot. Skid plate was stuck on with rusted bolts and a 1" square tube spacer.

Had to cut the square tube off to get access to the bolts and replace the nutserts with Black Magic kit.

Since the square tube was cut in half it wasn't going back on...so I ordered a SYE, a rear driveshaft, a cable shifter and two cheap Rough Country upper rear arms.

Had to have the rear uppers to set pinion angle to minimize vibes.

And then I quickly realized I needed adjustable track bars and steering...all of which I sourced from Currie to get the axles centered with my 4" lift.

Followed by an Oro Swayloc.

Then I wrecked two front tires... scrubbed all the tread off since my castor (or was it camber) angle wasn't that magic 5 degrees.

Bought Savvy adjustable control arms and everything was super smooth.

You're welcome to my temporary Rough Country upper rear arms if you want to pay shipping. They were a stopgap measure to get me back on the road and down the trail.

-Mac

P.S. Headed to Discount Tire this morning because since vibes are back since running the Rubicon... check out my Trash and Trail YT channel... guessing I scrubbed off my self adhesive wheel weights and the tires are out of balance.