94 Q45 transmission noise?

[ahardb0dy]

My wife drove the car yesterday when she left the house everything was normal, when she was leaving her first stop and moved the shifter from park to drive and still had her foot on the brake she heard a loud rattle noise she said she couldn't tell where the noise was coming from, she proceeded to drive home but the car felt like it didn't shift up, she put the gas pedal to the floor and the car started to go and than finally shifted, also the check engine light was on for a few seconds than went off, after that it was fine, no noise shifted normally , I checked the trans. fluid the other day and it looked to be full, smelled normal also. car has 159,000 miles on it. We just purchased this car and haven't done anything to it yet, nor do I have any history on any maint. that may or may not have been done to it, I've read on here about doing the trans. flush is that recommended at this amount of mileage? Would the onboard diagnostic thru the odometer show a problem with the trans.? Thanks