Comment by madaxe_again
9 years ago
Without hearing it I can't say for sure, but do you brake intermittently or continuously while going downhill?
If the latter, it'll likely be a caliper & disk getting hot and expanding, and rubbing, which can make an almighty racket - and then when they cool again they contract, meaning that a cold inspection would reveal little.
Alternately it's a wheel bearing on its way out, but that's unlikely on a new vehicle.
Does it get any better or worse when you apply steering, or not change at all?
Yeah check noise response to steering. I suspect CV joint problems. Very commmon, but often not disabling.
https://en.wikipedia.org/wiki/Constant-velocity_joint
I purposely brake intermittently. But, the brakes are definitely very hot when I've checked them.
I had wheel bearing issues with a previous older car, under similar circumstances. I checked steering, it doesn't seem to make much difference. The dealership dismissed wheel bearings as a possibility and said they checked the CV joint.
Their only theory the first time around was a small rock or something getting stuck in there and working its way out. The old "mud in your tires" sort of thing I guess (Joe Pesci reference). That's a mighty devilish rock.
when reading this, and from my own experience, I think it are the brakes. But only that it also happens when you don't break continuously. Could it be a CVT geared car has a lot less resistance on the engine, even in the L position, compared to manually geared cars?