transmission shifting rough on 2004 Cadillac DeVille

My 2004 deville has been a jewel. I just noticed the transmission, instead of a smooth transition from drive 1 to two, I get a rough"slam"ingagement and the same each progressive upshift. However when I hit passing gear, there is a smooth downshift.

by in Abingdon, VA on May 14, 2010
1 answer
ANSWER by on May 20, 2010
The powertrain control module may have detected a fault and as a result has commanded full line pressure causing the hard shifting. The first step would be to check for stored fault code(s) in the powertrain control module. Any stored codes should be diagnosed and repaired and then the transmission operation rechecked. If you need someone to access and diagnose any stored fault codes, please use the following link to find a shop near you -
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The powertrain control module (PCM) can fail causing stalling, and various engine and transmission drivability concerns.

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