Vibrations with a 2in lift??? help??

[trekn]

I just put in a 2in lift with poly spacers up front and rear shackles. I also just installed quadratec HD leaf packs. Since I have done so I get a noise between 35-40 MPH. I must also say that this is the first time in 9000 miles I rotated my new bridgestone dueler AT's. Could the tires be the rumble or the drive shaft angle. I also just had an alinment done on it, after the lift kit. Please help..


Rookie

 

[drifto77]

I just did the same lift on my 99, I had a slight vibe and found a wasted u-joint. Check them. Replaced both of 'em on the rear shaft and its gone.

 

[Highmiles]

I did a similar lift on my '99 as well - poly spacers up front and a RE 1410 AAL in the back. My vibes were drive shaft angle related. I resolved 99% of them with a 1" tranfer case drop and 2 1/2* shims.

Even though I'm not perfectly vibe free, my XJ is still smoother at 70 - 80 MPH than my father's '04 V8 Grand. I guess I've just gotten very sensitive to vibes since my modifications.

Sensitivity to vibes seems to be year related. The newer the XJ, the more likely even a small lift will cause some vibes.

RE: the U joint suggestion: would a U joint going bad seem more noticable after the lift? My guess is yes because of the increased angle.

 

[Kejtar]

I just put in a 2in lift with poly spacers up front and rear shackles. I also just installed quadratec HD leaf packs. Since I have done so I get a noise between 35-40 MPH. I must also say that this is the first time in 9000 miles I rotated my new bridgestone dueler AT's. Could the tires be the rumble or the drive shaft angle. I also just had an alinment done on it, after the lift kit. Please help..


Rookie

You rotated the tires, but did you balance them?

 

[HaZakated]

u need to drop you transfer case.....click the link for a TC lowering kit. this will fix your problem. it says 3-4" lift kits only but I did it and it is so smooth now.

http://www.quadratec.com/cgi-bin/sg...2&UREQC=3&UREQD=4&FNM=00&UID=2005031515575804

 

[Highmiles]

My suggestion is to search this site before taking a wrench to the Jeep or spending any $.

Do the vibe occur on accel? Do they get "better" when you are just coasting or on decel?

Balance vibes don't go away... they just get worse the faster the tire spins. You may not notice them until 40MPH, but they're there.

Comb through this site... you likely have a combo of both drive shaft vibes and some tire imbalance. It's too late for you, but this is why I try to change one thing at a time, lift the back, fix the vibe, lift the front, fix the alignment, then rotate tires. Just my two cents....

 

[Highmiles]

u need to drop you transfer case.....click the link for a TC lowering kit. this will fix your problem. it says 3-4" lift kits only but I did it and it is so smooth now.

http://www.quadratec.com/cgi-bin/sg...2&UREQC=3&UREQD=4&FNM=00&UID=2005031515575804

Rusty's offers one for $20 plus shipping (I think $28 total). You can also try to make your own.

 

[Kejtar]

Also, before you do tcase drop or shims take an angle finder to your drivetrain and measure the angles (search this forum for more info on that).