clunk when accelerating hard / strong regen
Hi, I have a 2017 Hyundai Ioniq 28 kWh with around 119,000 km.
When I accelerate hard, I hear a short clunk/knock once, then it’s quiet. The same happens when I brake hard with strong regen. With normal acceleration/braking there is no clunk, and when braking hard in Neutral there is no clunk either.
No grinding, rattling or continuous noise. I attached a video where you can hear it.
Has anyone had the same issue? Was it the reduction gearbox, driveshaft/CV joint, or motor/gearbox mount?
Also, if it needs repair: does anyone know a good workshop in Austria, preferably Vienna or the surrounding area, that can repair Ioniq EV motors/reduction gearboxes instead of just replacing the whole unit?
#Update 1:
I did some more testing today.
- The clunk only happens with hard acceleration or strong regenerative braking.
- If I accelerate and brake gently, there is no clunk at all.
- If I shift to Neutral and brake hard, there is no clunk.
- I drove about 90 km today at speeds between 30–140 km/h. No grinding, rattling, humming or other gearbox/motor noise.
-I also found an old inspection report: the front right rear control arm bushing was replaced in December 2025, so work has already been done in that area.