Hello Scotty! I am the original owner of my 2004 Honda CRV which has 130K miles on it (automatic transmission of course). I have a terrible rumbling noise coming from underneath my car during moderate to rapid acceleration. One mechanic allegedly repaired the rear differential a couple of years ago when the noise was relatively mild. It went away for a while but is now back with a vengeance and the vibration can be felt more toward the front, but still feels like it's underneath around the middle of the car. My regular mechanic doesn't seem to have an answer and chalks it up to the age of the vehicle. The rumbling goes away once the car is in motion. What do you think the issue is and what do I need to do to fix it? Thanks!
The issue is your so called "mechanic". Chalking up rumbling to "age" is a sad excuse for (a) not knowing what you're doing, and (b) running a poor business with bad customer satisfaction and finishing the job. Fire him and find a real mechanic.
it's most likely a worn part in the driveline, but it's going to require hands-on diagnosis to isolate the cause