Alright I'm a fairly new Volvo owner but I purchased an 86 wagon a few months ago with 200,000 plus miles on it. It is in good shape and starts, run, idles fine. Something weird though is that when im driving it makes a weird sound that appears to be coming from the bottom of the engine or tranny area. It's almost like a loud vibration or maybe a grinding type sound It doesn't happen when it shifts or when I stop or accelerate but at intermittent low speeds up to about 50 mph. If i speed up or slow down when it starts it goes away. It's kinda loud though when it echo's off the pavement. It doesn't appear to effect how it drives. If anyone has any clues please help. Nothing underneath seems to be loose either. Thanks in advance