When I put my minivan in reverse, it only slowly moves; even when the accelerator pedal is pushed. When I shift into Drive, there is a dull clump noise. What does this mean?
The reason you cannot move very fast in the reverse setting is you have an internal leak in the transmission valve body. The clunk is the valve body moving back the other way, and the clunk is the transmission engaging.
The problem is internal of the valve body; leaking fluid pressure between gears. The problem may get to the point where it will not move, so a transmission mechanic should test the pressures and diagnose and repair it soon, before it will not move.
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