AAL install, now vibration????

So the other day a buddy and I installed the AAL from Toytechlifts. Seems like a pretty straight forward thing to do IMO. I get out yesterday (1 day with it installed) and I get this horrendous vibration peaking about 25 mph - WTH?

Last night I get home and decide to loosen up the U-bolts. (I found the front driver side tight as all get out and the rears loose, the passenger side both front & back were tight but not feeling torqued and both sets were torqued properly the night before). I thought I'd drive forward 10 feet or so then reverse a few times to maybe help straighten out whatever the issue might be. I torque the bolts down and go for a spin, same thing???

When we removed & replaced the leaf pack we did not remove the shocks or unhook them (I don't know if that matters). Also the drive shaft may have slipped out of the rear end (it was close and my buddy had it hooked back up before I could get over to help.)

The truck (at the rear wheel) was raised about 2" if that makes any difference.

Anyone got any ideas??? Bueller? Bueller?

I've got a 1000+ round trip I'm starting tomorrow and don't like the idea of having to stop every hour to check the torque on the rear bolts from any vibration issues or have to worry about it

 

I don't think the driving back and forth will do anything. Just make sure the centering pins on the leaf pack fit into the holes in the spring perches and torque the U-bolts down to proper spec.

You may end up having to do axle shims and/or a Carrier bearing drop.

 

Try dropping the carrier bearing a 1/2". Its easy to do. Use a stack of washers, the two bolts are long enough to accommodate that much. If it reduces the vibe you know your onto something. You can buy kits that will drop it further.