Thumping sound from back BRAND NEW Z
 

Hey guys, got myself a 2019 sport about 2 weeks ago and 600miles into driving it, a thumping knocking noise started coming from the back everytime I started accelerating from a stop, second gear or reverse. Just one knock as soon as I shift. Sounds like an axle moving or maybe a strut?

I'll try to get it checked out at the dealership tomorrow but I wanted some input from you guys before I went in and looked stupid. If anyone has had this happen to them LMK.

hopefully its not what happened to my nephews girlfriend... see the tech notes from the dealer......

Kinda early for the oil-filled diff bushing to be leaked out/ but they do have movement in them...I’d definitely re-torque the lug nuts.
Lift carpet & cover up in rear and inspect spare tire & subwoofer mounting to ensure tightness.

More than likely it is you. You will become smoother with your shifts/acceleration with some practice. Nothing is wrong with the car.
You're not the first person to have this issue.

1st and 2nd gear are pretty notorious, sometimes Im perfect and sometimes it feels like my first day...

But also could be the diff bushings... hard to believe it would happen so soon tho...


Also, check for Ravioli cans under seat... LMAO

I'm with JC in that it's probably unlikely to be the diff bushing, but it's pretty easy to check. Look under the rear of the car for signs of fluid leaking out of the bushing at the rear of the differential and/or streaks running down the subframe member in which it is embedded. It will be obvious - a lot of time it explodes and sprays fluid all over the diff housing as well.

The sad truth is, Chef Boyardee can be really hard on a car over time... especially our Zs.

Guess Imma have to get that can of ravioli out from under my seat then...

My sides...
https://i.imgur.com/ea7OFiW.png

Whatever it is just remember that when its dead its not a call girl...it's a hooker.

How much does a dealer charge for a chef-boy-r-dee extraction, anyway? :rofl2:

At least they didn’t charge for the reciprocating muffle bearing, the henway and the pie cost...

Here is exactly what is happening. You have 3 mounting points for the diff. 2 in the front and one gel filled one in the back. When your shifts aren't smooth enough, the front of the diff will move up and contact the rubber bushings in between the diff and the subframe. That is where the thump is coming from. You will figure out how to deal with this over time with the clutch and throttle input. It is really nasty when those bushings go out or are not put back in after a diff change.

Check passenger seat belt. It can bump on the plastic if it's not in it's normal position. Had this happen a couple of times so far after having a passenger in the car. It was "WTF is that?" until I noticed where it came from.

Back in the day when I was working as a mechanic. We had a LTD come in. The owner said that the local Ford dealership couldn't find the thumbing noise when he made a right turn. Took us 3 days to find it. One guy drove the car, and another sat in different places. What we found was a wrench hanging behind the rear seat, off to the left side. It was hung with mechanic's wire. With a note attached to it. The note said "I see you finally found your noise." :rofl2:

Or the guy who couldn't find where the smell was coming from. :eek: Pulled up the carpet and found a half eaten lunch from the factory guy. :rofl2:

I would check the rear diff bushing. If you have done any hole shots. And banging the gears. That's where I would look first.