We just bought a 1999 Mitsubishi Montero Sport LS. We got a great deal but on our way home we noticed a very fast vibration that seemed to come from the back. I at first thought it was a bad road. It actually felt like I was hitting the rumble/safety strips on the side of the road. It seems to be starting anywhere from 35-45 but it is more when you are have slow down and speed up. Once you get to a consistent speed usually 55 miles per hour it stops. I took it to the tire store and had my brakes and tires checked. They said it feels like the 4wd was starting to engage. I also have a consistent flashing on the dash of the 4wd and at times the anti brake light comes on and the turns off. Please if anyone can help.

Thank you so much,
Cris