hey there everyone, we had gotten our tranny flushed about a week or two ago and then went downstate and experienced some hard upshifting a few times , since we have gotten back its done it repeaditly but not all the time, we've taken back to the garage that serviced it and they checked it somehow and drained and replaced the fluid again, the place weve taken it is very reputable and htey do good work. there not a small little garage though they are local, anyways we know that it was done right but why is it shifting hard jsut after the tranny being flushed? I have a GM/PONTIAC TSB for it saying that if the customer complains about hard upshifting that the Pressure Control Solenoid Valve Assembly needs to be replaced in this case, but id like to get all of your wonderful opinions first! Thanks in advance for any help! Also the trans checked out fin it the shops so called test?! whatever they did it didnt fix it though its not anyworse! Oh and the tech took the car for a ride and it didnt act up at all for him, he too it for about 7-9 minute drive at about 45/50 MPH... Why doesnt ever act up ehn the techs drive it?!?!?!
Anyways when he gave us the keys he said; "WOW that is a really nice car, real nice!"
Thanks again for any advance help!

i had the exact same problem!! I added the lucas addictive found at ricerzone, and it did wonders. Mine was especially bad in the 1-2 shift under low to medium throttle, however after the lucas went in 95% of the slip went away. Sadly, my tranny is still messed up and is now in the shop getting repaired at the cost of $980, but i say try the lucas as its only like $7 bucks and may be the answer your looking for.

Before you consider using Lucas Additive, check this out.. it might change your mind

http://www.bobistheoilguy.com/images/lucas/lucas.htm