When I'm driving on a flat Road
and then hit like a little downgrade
in the road and then the road I'll go
flat again my transmission will
shift is that normal
Likely but the trans is just as important as the engine but is often neglected, I would recommend regular maintenance, but not a power flush, but general fluid & filter changes and check you sensors connections. If there is a check engine light on get it read to see the codes.
Search Chevrolet Impala Questions
Chevrolet Impala Experts