2000 hd shutter
My brother and I were driving the other day and normal driving conditions, we had been on the highway a few hours and we came to a merge and I think the transmission dropped down into overdrive and it started bucking and shuddering. So we weren't sure what it was all I really cared about was getting home. It only did this on low rpms tho, once the foot was put into it, everything was normal. What could this be?