It had a loud noise every time it switch from the ICE to battery or back. It sounded something like a rusty spring or something of that sort. It was loud enough that I could hear it from inside my house while my truck was parked in the driveway and running. At first they retried to tell me it might be normal until I asked them why it didn’t do that when I bought it. Purchased June 2022, 5700 miles on it and not mud or dirt roads to this point.