Some times it is not a broken PCS but a sticky gummy varnished one.
Same goes for the overall valve body/check balls in there.
Here is what you can try to eliminate P1811 Max adapt long shift code.
First off add a can of TransTune, this will clean things out well, say bye to varnish & hopefully better shifts when hot.....
Trans Tune | Sea Foam Sales Company
Next after driving 1000 miles with the trans tune in....drop the pan again, use a GM filter, and install a shift kit by TRANSGO!! Installs into the accumulator accessible inside bottom of transmission pan.
TransGo | 4T65E: SK 4T65E
This should provide tighter shifts when hot by passing the need for removing the valve body to change out the PCS.
Refill with the modern synthetic Dexron VI (6)
done with problem free shifts.
97 and 98 Park Avenue with hard shifts