so when i go to pass someone, or when i'm making a turn and i'm giving it some gas, the rear end wants to squat & squirm to the side (depending on which way i'm turning, obviously). i'm about to go take some photos of the facts stated below, to make it easier to see what i'm talking about.

here are the facts that i have at the moment:

1) there are signs where the driver's side rear wheel is rubbing the wheel well



2) the driver's side bumpstop in the rear is completely gone (and i've heard metal-to-metal at times when it bottoms out)



3) the top bolt on the UMI adjustable torque arm is banging the driveshaft tunnel, causing it to dent the sheet metal where it hits (on the driver's side)



4) **removed**

5) the sway bar has slightly more than two fingers of gap between the bar and the rear housing on the passenger side, but slightly less than two on the driver's side



i've checked the rear sway bar and the endlinks, they are solid, the mounting brackets for them are still gripping the metal tabs that are welded to the axle tubes, and there are no signs of them slipping at all.

the springs are seated correctly on top & bottom.

the panhard bar (UMI double adjustable) is solid as a rock, there is no give whatsoever, and when the wheels are on the ground, the rear end is centered to within 1/4" tolerance when measuring from the lip of the rims to the top center of the wheel well.

i can't see any signs of the PHR mounting points being cracked/bent (no dimples/bubbles/cracks in the paint that would show up if there were flex points in the underlying metal).

i tried jacking up the bottom of the spring mount on the rear axle itself on the driver's side (the one where the spring is bowed), and it doesn't change the bow of the spring at all....i was thinking that maybe the welds on the axle tube(s) broke loose and was allowing one or both sides of the tube to rotate, but it doesn't seem to move at all, even when i put my full weight on the axle with the jack under the spring mount.

the springs are Strano's, and the shocks are Koni's, both less than 3 years old.

 

The track bar is the only item that controls side to side and centering.

If the rear is shifting back and forth you could have a bad heim or possibly a broken bracket at the rear side or at the body...
Make sure you checked it good, you grabbing it with your hand is not the same as the load on it from the car...
Use a big pry bar and see if you have any movement..

When you jack it up like that and let it hang nothing is going to be centered since the bar is going to pull it to one side..

 

ok, here's an update.....item 4 was removed, i figured out that the spring was bowed out because when the rear end drooped while it was jacked up, the rubber mount at the top shifted and made it look funky. i was able to grab a coil of the spring on each side and pull down on it, then push it to the side, and it snapped back into place....so the rear springs are fine. it looked seated fine at first, but it was apparently off a little bit.

didn't get to look at much more, as i was in the process of installing some sound deadening material, and needed to get as much of that done as i could while i still had light.

 

Do you have stock LCA's, if so maybe the bushings are shot and allowing the rear to move around.

 

no, i have UMI Poly/Roto LCA's....got rid of the stockers long ago

 

is it possible that one of the shocks is bad?

what rear springs are you running?

 

i haven't had a chance yet to check the shocks, but it seems OK during normal driving....it's only when i'm turning and accelerating at the same time that it seems like something's wrong.....but anything's possible, i'll have to find some time to pull them and check them out.

as for the springs, it's Strano springs on all 4 corners

 

The axle won't move unless the control arms or panhard bar let it move. I'd examine those three things very carefully.