Vibration while accelerating

Semper_Fi13

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Mar 2, 2022
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SE GA
So ever since I put the 2.5 inch lift in the tJ I have noticed a vibration while driving. It’s mainly when I am in the throttle. It feels like I’m skipping the tires. We have checked the u joints and all are good. My drive line seems to be at a good angle also. I did go up in tire size to 32 11.5 15. Does anyone have any idea on what it could be.
 
You either need a:
- Transfer case drop
- motor mount lift
- slip yoke eliminator and DC driveshaft

All of these are possible solutions to the geometry change you put on your driveline.
 
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You either need a:
- Transfer case drop
- motor mount lift
- slip yoke eliminator and DC driveshaft

All of these are possible solutions to the geometry change you put on your driveline.
I though that you don’t need a SYE on anything under 3.5 inches?
 
Ok it looks like the easies way would be transfer case drop
When I did my first lift (also 2.5”), I just added stacked grade 8 washers between the skid plate and frame rail until the vibrations went away. It’s not the prettiest solution, but I liked that I was able to fine tune and get the least amount of drop possible. I think I needed somewhere around 1/2” stacks.

Later I did a body lift and motor mount lift to help fit bigger tires. I was able to remove the transfer case drop with the motor mount lift on.
 
I would try replacing your ujoints first. You may need a drop or MML, but I would eliminate a worn ujoint first.
 
So you think motor mount lift would be better? I’m not doing a body lift
How important is maximizing ground clearance to you? A MML without a body lift will require you to mess with moving the fan shroud and possibly some other stuff. Overall a fair bit more work and expense than adding a few washers. If you really want to keep that 1/2” clearance then go for the MML.
 
Watch the first 3 minutes of this video. Really you should watch the whole thing, but the first 3 minutes will show you the effect of lift on drive shaft angles. The angles are what are causing the low speed vibration. In the video we are demonstrating how a 3" lift affects angles, I know yours is 2.5", but the overall effect on angles in going to be very similar.

As far as lift not needing an SYE and double cardan shaft for lifts under 3.5 or 2.5 or whatever number. I disagree. I of course have a uniquely biased perspective. But that perspective is not based on selling drive shafts so much as it is on my understanding of ideal operating angles of drive shafts and being a bit of a perfectionist in my definition of what "works". That is really the key, defining what it means to you for something to "work". If all that means is that when you press on the gas the Jeep moves forward it is pretty easy to accomplish that goal. If you are more concerned about getting the best performance out of your driveline, the smoothest operation and the longest wear life, the SYE and double cardan shaft is recommended. Generally though, regardless of lift height, I think it is best to prescribe treatment based on the symptoms. If someone has a 3" lift but tells me that they have no low speed vibrations from their stock shaft, I don't see too much of a problem and don't like telling them they "need" an SYE. But if someone does have those low speed vibrations I think the correct way to fix them is with the SYE and double cardan shaft.

 
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So I have the double cardan already up front on my Jeep already. I am just getting a Shutter pretty much up until 35 40 mph. But I still can feel a little bit of vibration at higher speeds. But it’s really bad in first second and started out in the third
 
So I have the double cardan already up front on my Jeep already. I am just getting a Shutter pretty much up until 35 40 mph. But I still can feel a little bit of vibration at higher speeds. But it’s really bad in first second and started out in the third
A double cardan on the front shaft or a double cardan at the front end of the rear shaft?