Hi windmariah@hotmail. Com. Welcome to the forum. What you're describing sounds typical of a broken belt in a tire. Jack the rear end off the ground, block the front wheels, then run it in gear while watching the tire tread for lumps in the tread or squirming back and forth sideways. Typically only one wheel will spin. Block that one to make the other tire spin but be careful. The tire will cause blocks to shootout if it grabs the tread. The broken belt can also usually be seen when it is spun on a tire balancer.
A loose wheel can cause this too but that won't last long. The wheel would have fallen off by now. A bent axle could do this too but it would not be intermittent.
Tuesday, June 8th, 2010 AT 5:31 PM