Transmission Problem

I have a 2000 Impala LS with the 3.8l engine. Recently it started to start to show a transmission issue. 1-2 and 2-3 shifts are fine. When it goes into lockup in 3rd, then the car shudders (shakes). In Drive it seems to be fine. The problem seems to be more apparent when the engine and transmission are cooler. There are no codes when I scanned. Any suggestions/comments as to a possible cause of the problem would be appreciated. Thank you

I have a 2000 Impala LS with the 3.8l engine. Recently it started to start to show a transmission issue. 1-2 and 2-3 shifts are fine. When it goes into lockup in 3rd, then the car shudders (shakes). In Drive it seems to be fine. The problem seems to be more apparent when the engine and transmission are cooler. There are no codes when I scanned. Any suggestions/comments as to a possible cause of the problem would be appreciated. Thank you looks like the pressure control solienide,most of the impalas have this problem ,it won't show a code because it stores it,anyone with a scanner at a tranny shop can find the hidden code,you can disconnect the neg terminal on battery for a min or so and it might take care of the problem for a while but it will come back,if so keep un hooking it till you can get the pcs fixed,its about a 6- 8 hour job,the cradle has to be let down in order to get the side cover off the tranny to repalce the shift solienide

Thanks for the input. I did replace the pcs one time before for a hard shift issue, not too bad of a job. I will get the solenoid and go ahead and replace it. Thanks for the help.

Jeff

have you changed tranny fluid and filter? after about 100.000 mls on those trannys if you don't main tame them that's when trannys start slipping in the 3.8 or 3800 motor's.

Thanks for the input Scrapper. The car has 80,000 mile. I did change trans fluid and filter about 10,000 miles ago.