So it looks like I've got the infamous Pressure Control Solenoid problem on my '04 Silhouette. When it warms up, it sometimes shifts hard. Turn the van off. Let it sit a minute. Turn it back on, shifts fine. Everything points to the Pressure Control Solenoid. My question ... is letting it go like this indefinitely going to cause me more problems in the future? I really don't have the money right now. I know the part itself is cheap but the labor is intensive for this problem so it can run over $500. Am I hurting the van by letting this go? My wife and kids don't even notice the hard shifts. Just me because I'm a guy and I notice these things, and it bugs me when it does it.

Welcome to the Forums! Probably the best place to start is having the van scanned for codes incl transmission codes. The P1811 long adapt shift may very well show up.
Have you serviced the transmission lately with a new filter & Dexron VI (6) fluid change?
This also allows inspection for any particles inside the pan.
When my Buick was acting up and had hard shifts, I added a can of Sea Foam Trans Tune. Trans Tune - Sea Foam Sales Company
which really helps to remove varnish, drove around for 750 miles or so (which did make shifts smother) and then did a shift kit and new fluid & filter in the 4T65e. All is well now.

I had the same issue and had drove it for about 2yrs. Well it final broke the torque converter. I wouldn't ignore it to long. It is worst on the trans when days that are hot. It will break and leave you on the side of the road without any warning. There are some really good Youtube videos on how to replace this. Its just a time consuming project. About 4hrs to a whole day to replace the solenoid. Cheap fix, new trans is $1250-$1800.