1983 AMC Eagle • 100 miles

I have a 1983 AMC Eagle wagon, 258/4.2L motor, auto transmission with just over 100,000 miles on it. At 45 mph the car starts to rumble badly, up hill, down hill, level it doesn't matter. If I drop down to 35 mph it goes away but comes back at 45 mph. If I drop down to 2nd gear (3 speed auto) the rumble goes away and I can take the speed up to 50 or 55 mph, don't want to go faster then 55 in 2nd.
Eagle owner
September 3, 2012.

I would look at wheel bearings front and rear to check for failures. Check the tires as well for wear.

It could be in the trans but there are not many bearings that can make this noise.

The differential bearings could also do this.