Why does my BMW bang when I brake and turn? A loud bang when you brake and turn can come from a broken transmission support, not just brakes or struts. On this BMW 335, that was the cause, and the fix was a new support and mount.
The problem
This BMW owner heard a loud banging from under the car when turning and braking. Another shop had replaced all four wheel brakes and done an alignment, but the noise stayed. The shop then suggested shocks and struts, even though nothing had pointed to them.
Why noises are hard to diagnose
We tell our staff that most of diagnosing an issue correctly is verifying the customer's concern. If you can't reproduce the noise, you're guessing. Guessing means parts get replaced that were never the problem.
How we found it
- We took a ride with the customer to hear the noise ourselves.
- A Master Technician pulled the car in and inspected it.
- In about a minute, we saw the transmission support was broken right in half.
That support holds the transmission in place. When the driver braked, the car downshifted and the transmission banged against the body.
The fix
We replaced the support and mount within one day, and the customer was back on the road with the noise gone. Brakes and struts weren't the issue, and neither needed work.
Noises you shouldn't ignore
- Banging or clunking when you brake, turn or shift.
- Noise that changes with speed or gear.
- Vibration you can feel through the floor.
Questions we hear
Can a bad transmission mount cause noise when braking?
Yes. A broken or worn mount lets the transmission move and hit the body, especially when the car downshifts.
Do you work on BMWs?
Yes. See our BMW repair page and our diagnostics service.
Have a noise nobody has solved? Book a visit at our West Springfield shop and we'll take a ride with you.
