New SYE and CV vibrates at 70 mph

[EROCK]

Just had a jeep shop put in a SYE and CV. I'm on 4"s of lift. They readjusted the adjustable control arms of for the new geometry. Now I'm getting driveline vibs at 68mph and gets slowly worse the faster I go.

 

[JMT]

Pinion angle looks too high. I’d suggest trying to lower It.

 

[tworley]

X2. Just a hair high it looks like

 

[Flivver250]

That adjustment is tricky. Use the RCH scale. Shorten the uppers 1/2 a turn and try it.

 

[whitrzac]

Could be tire ballance/wear issues too

 

[Goatman]

Looks like the transfer output is dropped too (I only have a phone to use. So I may be completely mis-eyeballing it)

 

[EROCK]

Looks like the transfer output is dropped too (I only have a phone to use. So I may be completely mis-eyeballing it)

That's the wide angle lens I took it with. Trying to get everything in there. He's a flat lens pic for ya.

 

[Bigfoot-NM]

Still looks like the pinion angle is too high. Do you have an angle gauge to measure pinon angle and driveshaft angle?

Ideally, you want the rear pinion angle in relation to the driveshaft angle to be between 0 and -2 degrees. (Meaning the pinion angle should not be higher than the driveshaft angle)

 

[EROCK]

Checked with an analog angle finder today and got roughly the same angle with both. Maybe 1/2 a degree difference if any. The shaft read 16 1/2 then 17 1/2 the 17ish. The diff read 16 1/2 every time. My angle finder sucks. So with them being so close, should I raise it or lower it (shorten or lengthen upper arms) slightly to see if it goes away? Also does this shaft need to be ballanced?

 

[xxdabroxx]

I'd start by lowering it personally.

 

[EROCK]

I think a half turned helped it. It's been pouring all day so I haven't got to try it excessively however I got to 75 today and definitely had less vibration though it still has some. I think one more half turn might do the trick.

 

[EROCK]

I've made three adjustments. All result in the same drive line vibration at 70+

 

[EROCK]

I'm wondering if the the drive shaft needs to be balanced. There's no weights on it.

 

[DrDmoney]

That's the wide angle lens I took it with. Trying to get everything in there. He's a flat lens pic for ya.

View attachment 122280

pinion angle too high, as mentioned before

 

[chino1969]

I wouldn't do a damned thing to it. You just spent good money having a shop do this work. Let them get it right.

 

[DrDmoney]

Checked with an analog angle finder today and got roughly the same angle with both. Maybe 1/2 a degree difference if any. The shaft read 16 1/2 then 17 1/2 the 17ish. The diff read 16 1/2 every time. My angle finder sucks. So with them being so close, should I raise it or lower it (shorten or lengthen upper arms) slightly to see if it goes away? Also does this shaft need to be ballanced?

the pinion angle should be lower by a couple of degrees because it will rotate up higher under power the front DS does the opposite when engaged.

 

[EROCK]

pinion angle too high, as mentioned before

Pinion angle was 0 degrees. It vibrated. It's now down to 3 degrees still vibrates. Are you saying the angle out of the transfer case is too high for the double cardon end?

 

[DrDmoney]

Pinion angle was 0 degrees. It vibrated. It's now down to 3 degrees still vibrates. Are you saying the angle out of the transfer case is too high for the double cardon end?

No, that end should be fine, your Pinion should be pointing a little lower than your DS. I use the mounting surface of the yoke to measure, you should be able to get your angle finder on the edge just make sure it’s rotated so you are getting a plumb measurement

 

[DrDmoney]

I clamp a framing square to the yoke and zero my angle finder on the DS then read the angle on the square.

 

[DrDmoney]

Here’s an example

which control arms do you have? Are the bushings worn out?