200-4r line pressure loss over time

[Kawaiikeno]

I'm seeing line pressure loss. A few years ago it had 80-90 psi at minimun tv at idle and 275 give or take at full tv at 2000 rpm .Last year minimun tv was still around 80-90 but full tv had dropped to around 250 max. Now this year idle tv pressure is still around 80 psi but the only time it will go over 250 psi is in park the rest of the time it has a hard time breaking 180 psi. It has a 13 vane pump with about 50,000 miles since rebuild
Does this sound like the pump is failing or time for a fresh up? all the shifts are still very firm and everything else feels normal.
Thanks in advance for any ideas
Mike