Rear wag under decel
 

Just a quick question regarding my car. A few hundred miles ago I developed a "wag" in the rear of the car when I down shift and let off the clutch off throttle. Never did that before. I'm not talking about dropping the clutch, just coming off a ramp on the interstate and down shifting and easing off the clutch to slow myself a bit, the rear end will wiggle side to side a good bit. Could this be in the diff? No other recent weird issues that I could relate to this. It worries me a bit and feels unsafe. I will be able to check in a week or so, my FCM parts are on the way and i will be able to check back over everything. Ever since about 6 months ago, something hasn't felt right in the suspension, I just haven't gotten off my ass to look. I have all new bushings, shocks, sways and sway bushings/mounts, so I shouldn't have any slack anywhere. I wish I could justify replacing the diff mounts, but I wanted to save that for the gears, which don't look to be coming any time soon. I may go ahead and do that soon as well. I'm confident they are sloppy. Ideas?

If you have recently installed new bushings, check for anything loose as far as nuts and bolts, also check your diff bushings and drive shaft u-joints. Sounds like under load it is taking up the slack wherever it is and loosens up without load.

it could be as simple as a marginal toe-out on the rear that pulls itself straight under acceleration

or it could be a loose bushing.

A string test could tell you if it's the first one. putting the car on jackstands without shocks will tell you if it's the latter.

I will test the latter one when my parts get here next week. The first one is also possible. alignment was perfect, but a cam bolt could have slipped. By eye the rear still looks good though. Then again it was already so close to maxed out, if it did slip it wouldn't have gone very far.