Heres a good question, are the drive wheels in nuetral, if you can figure this out it would be a great help. I bet they are, and if this is the case, the bolt which would determine the 1,3,5 to 2,4 motion is broken (it also helps the back and forth mtion).
Also try and move the smaller lever of the two back and forth (if you have it). Does it want to return back to center?
