Check your muffler pipes.
It turned out to be the alternator going bad. Replaced alternator. No more growling.
A noise coming from the back of the throat, like the growling sound a dog would make.
Something is out of balance, maybe the water pump is on its way out.
check your wheel bearings.
Worn Ball Joint
if its a front wheel drive vehicle then it could be the axels
It depends on the type of bear or their feelings. It could be growling really loudly to protect its family, or just softly growling at their cubs. I hope that helps! You can always research about bears because they would definitely have their characteristics on a fact file page :P
I would have your exaust pipe looked at, it might be loose, or might even be missing a bracket.
Well without further analysis or information, a short answer would be that your engine is BROKEN.
It may be your catalytic converter. Ours did the same thing with an automatic transmission. We sometimes thought it was the transmission, then we received a recall on the converter. Took it in to be replaced, and no more rattling.
Could be a worn out shock or wheel bearings. Is it 4 wheel drive?
A baby in the back (with a rattle of course), or a rattle snake under the seat