[Orlando_87GN]

One of the great things about an interactive message board is you can pull from others experiences. If your transmission had anything done to it for $300 it's probably wasted. There are a select few people in the country that can successfully work on the BRF transmission in the Buick, because it's calibrated differently than what they are used to, like something that came in a Monte. If your local mechanic messed with your stock transmission he's most likely caused a problem. The most common disaster is installing a shift kit without realizing the transmission isn't like the others, installing a converter with the wrong stall speed or hell, your original transmission might be sitting on the shop floor somewhere all the while the mechanic thinks he gave you a better rebuilt transmission. Worst case scenario is he took the valve body off and switched it with another or put it all back together with Monte Carlo or 'Heavy Duty Limo/Taxi' directions. Before you blow it up or fry the clutches you need to get to the bottom of what was performed, probably undo the changes or send your hopefully original transmission to one of the trusted vendors that can handle the job. There is nothing worse than a fine running Buick with a bum transmission. It will make you want to set a match to the car. Been there, done that, got the T-shirt.