2016 z51, non mrc, 30k miles. A8.

When driving the car, straight usually. At 55+ the car feels super all over in the rear end. Scary really. A lot of roll. I broke a axle not long ago and replaced it with z06 axle. Just on the side that broke. And bought new rear tires. Before the axle broke. Car was fine at any speed. Super safe feeling.and after I replaced it, been scary ever since. So far to fix this issue I have took it to the dealer, for a alignment, while it was there did the trans flush. Got 4 new shocks. I’m waiting on rear end fluid and going to change it. Bc it is a little low. But I took the cheap tires off thinking it might have been the floating feeling I was getting. Put 4 new Michelin pilot sport as3+. Still feels sketchy. Wondered if gm got the alignment right. So took it to a local. Who has the angle tool for the rear. He got it dead on the specs I found here for street driving, still awful. It’s turning my hair gray. I do have a gm axle that is for the car. Is there any way the zo6 axle is making it weird? It was used. But only had 150 miles on it before we put g force in. I’m stumped. Any one want to chime in. New tires, new shocks, alignment. What else is there to make it act like it’s on marbles past 55 mph

 

How did you break the axle?

 

Trying to get a good 60’ lol, all jokes aside. I was just taking my brother for a ride. We stopped in the road, loaded it up and hit it. Broke on the hit. But it didn’t brake the axle. It was the cage where the 3 *****? Are

 

Okay, my best guess is that you have loose hardware - A arms, roll bar, transverse spring, etc. Re-torque everything.

 

Something happened when you broke the axle and/or when it was replaced.

Get it somewhere immediately where you can get it up with someone who knows what they are doing to carefully check it out. Then, inspect everything else from alignment to tires, since those are also suspect until otherwise "cleared." All the best and let us know what you find, please.

 

I agree 100% OP dont drive it no more you could end up in a bad wreck with it like it is. Something bad could be wrong in the end.. Robert

 

May be onto something. The zo6 axles is for a m7, even tho it fit. Could this be the issue.

 

This might sound crazy, but check your air pressure. I had a gauge go bad a while back and it was reading low-actually had more psi in them than I thought. Dropped psi down-all good.

 

It was the axle. All good now.