TCC solenoid on 1998 Subaru Legacy

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
car has 152,000 miles, rebuilt trans (10 months ago) has 20,000. use on a paper route, so rough treatment. Got a P0740 code. Son has replaced a TCC solenoid on a couple of other cars, but never a Subaru. Does valve body have to be removed to replace solenoid? He's worried about bearings inside the valve body. Could he mess something up by removing it? Any special care have to be taken while handling it? He would like a diagram but all I can find is downloads for a whole manual. Is there something else we should check before replacing the TCC solenoid? Basically anything you can tell me would be helpful. Thanks so much!
(1) Answer
Here is some info for your son:
I would recommend the entire manual if your son is going to work on this, it will come in handy for other repairs as well.