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Slight Wobble After Lift


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Have not done a alignment yet but I don't think it's that it is almost like a u joint feeling a vibration at 15 mph and above and it is a 4.5 lift and it didn't have this problem before so it's gotta be something with the lift

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If you have not had an alignment after that much lift your toe setting is going to be way off and your caster angle will have changed. I'm sure your old u joints are feeling the pain as well. They don't like changing angles after being in one spot for a long time either. Change your u joints and DO an alignment. Your steering wheel probably isn't centered anymore and your front tires will start wearing badly. This is a must do.

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Have not done a alignment yet but I don't think it's that it is almost like a u joint feeling a vibration at 15 mph and above and it is a 4.5 lift and it didn't have this problem before so it's gotta be something with the lift

Take out your front drive shaft and drive it again.

 

U-joints don't like changes to their operating angle. Your lift may have changed the angle on your front u-joint enough to induce a vibration.

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90% of the time it is the track bar/track bar bushing.

 

At what speed does it happen? Does it happen every time? And does it need something like a bump to 'start it'? Also can you please post a picture of your steering? (straight on from the front)

 

 

 At 4.5"I would lean towards guessing it's the rear DV vibrating.. But thats normally not an issues on the older models.. but his lift could be more than 4.5

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I mentioned to make sure about the caster adjustment because it is usually overlooked when doing an alignment because it is not a tire wear issue. Most shops you go to will do a toe and go. And most guys doing a quick lift don't think about it either. This is one that needs mentioning and adjusted. Especially on our trucks.

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ok guys Ive made sure everything is tightened and its getting aligned thursday just thought I would post pics to see if any of you guys can tell what might be causing vibration at 20mph

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Let me know what you spot thanks guys.

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Rear drive shaft u-joint angles.

 

All wrong.

 

Agree. No way the rear diff pinion should be pointed up that much unless you are using wedges or something. It's like the leaf spring center bolt isn't in the lower plate hole and the axle is rotated upwards so the pinion is "looking at" the tcase output. Looks like it's set up for a CV drive shaft. Might be your pic angle, but the below is the proper geometry your drive shaft should be at.

 

2joint_angle.gif

 

This is where you are.

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The two u-joints on a drive shaft have operate "in phase" or they set up a vibration. To be in phase, the two u-joint angles have to be the same (within about a degree or so). Look at the diagram Don posted -- the angle of the mainshaft through the transfer case is parallel to the angle of the pinion shaft in the differential. That makes the two u-joint operating angles equal and opposite, so any vibration gets cancelled out.

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Rear pinion is too high ... front pinion is too low ... the rear will cause a vibe itself, the front even more so ...

 

The rear angles should be equal as the info posted above shows. With a 1 to 2 degree down angle.

The front pinion should be pointed directly at front output yoke with a 1 degree up angle.

 

Fix those issues and you will kill your wobble.

 

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