My Brother just picked up a 90 Bronco, 302 with the AOD Transmission. Anyways around 1200-1300 RPM the Truck bucks like it wants to shift, than it settles down, than it does it again and again unless you give it gas to get to a higher RPM. It has 100,000 miles on it, we replaced the Tranny Filter figured most people neglect to do it, this helped a little but the problem is definately still there. Any ideas what this could be, does it need a rebuild?