Michigan Southeast Michigan Lift/Suspension Specialist Needed

[StimpsonJCatt]

Hi Everyone,

Recently had a 3-1/2" Rock Krawler belly up long arm kit (I know LA's aren't a fan favorite on this site) installed and with this being my first Jeep and first lift kit, I am not sure what to expect but have a lot of vibration now and looking for someone in my area familiar with TJ's, lift kits and can help diagnose if something needs to be updated. I am kinda bummed if this is the new norm. In addition to the lift kit, the full details of the build are below.
- 1.25" body lift
- Fox shocks
- Adams drive shafts
- Rear upper spring perches had to be moved rearward to rotate the axle enough to set the pinion angle
- Changed gears to 4.88

Ironically after the build was done, the NV3550 trans went out so I replaced the trans and clutch with a Novak AX-15 trans and Luk clutch.

Any help would be greatly appreciated.

 

[NashvilleTJ]

Hi Everyone,

Recently had a 3-1/2" Rock Krawler belly up long arm kit (I know LA's aren't a fan favorite on this site) installed and with this being my first Jeep and first lift kit, I am not sure what to expect but have a lot of vibration now and looking for someone in my area familiar with TJ's, lift kits and can help diagnose if something needs to be updated. I am kinda bummed if this is the new norm. In addition to the lift kit, the full details of the build are below.
- 1.25" body lift
- Fox shocks
- Adams drive shafts
- Rear upper spring perches had to be moved rearward to rotate the axle enough to set the pinion angle
- Changed gears to 4.88

Ironically after the build was done, the NV3550 trans went out so I replaced the trans and clutch with a Novak AX-15 trans and Luk clutch.

Any help would be greatly appreciated.

Is the new rear driveshaft a double cardan?

 

[StimpsonJCatt]

Is the new rear driveshaft a double cardan?

Yes

 

[bbaldwin237]

Sounds like it would be the wrong driveshaft angle. Take a look and make sure that the pinion appears to be pointed at the transfer case output. If it wasn't set properly for ride height it could be off a couple degrees causing vibrations.

 

[StimpsonJCatt]

Rear drivetrain is theoretically setup correctly per the CV illustration, but I have not personally measured/verified the pinion angle. Would be a good sanity check to do to confirm it is correct. I do know there has been some adjustments since first install.

 

[bbaldwin237]

Are the arms double adjustable? Meaning they have a fitting and nut on both ends. Did the vibrations start immediately after install or after some miles? If it started later, it's possible that a jam nut wasn't tightened properly and the arm moved a bit. It's also possible that the axles aren't squared properly after the install.

Also, are you pretty confident that it's a drive line vibration and not maybe coming from the tires?

 

[StimpsonJCatt]

Control arms only have one jam nut and the vibrations have always been there. Jeep still doesn't have 100 miles on it since the all the work was done including the trans. Stupid winter got in the way here in Michigan (LOL!!). There were no vibrations before the work so wasn't really focusing on tire balance but who knows, maybe a weight or two fell off at some point.

Wondering if maybe the axles aren't square. Will look into that and what the pinion angle is set at.