Hello, I had a full service done on my Prius last week. It has done just over 175k miles and a few days ago the engine started making a growling noise. It is mainly when I am accelerating (but not in battery only mode), it contains to growl if I put it in B to slow down. I have had the bearing changed in not front tyres recently and I had the hybrid battery replaced last year when it died a death. Has anyone come across this sort of thing before? I was guessing an exhaust issue but I am hardly an expert on cars!!!
I'm guessing you've tried to reproduce it by revving the engine while in park? It only happens under load? Mechanic's stethoscopes are inexpensive, or you can use a length of heater hose, to check exhaust joints. Have you looked at the transaxle oil? Are the CV boots intact?