[Alvy]

Have you looked at your relief valves? Are they manual or automatic? Manual ones have small buttons sticking out of the top. Look to see if they are stuck down if it has them. Still a good idea to change fluid with filter. Did you check the fluid level again? Does it sound like it's straining or cavitating? Fluid you can see May look good but doesn't mean that the rest is.

Your trunnion wear looks normal.

Also look for sheared pin in drive shaft, it's common. Make sure that you're linkage is moving as it should, not too much goes wrong with these other than what's listed