Toro Hydraulics Slow

I have a ZX4800. The left side hydraulics take a long time to warm up (15-20 minutes). I have to go back and forth at low throttle to get it warmed up. I usually get a couple seconds of normal movement out of it, then it drops to nothing, and then slowly works it's way up to normal function, usually making creaking sounds as I press the hydraulics fully forward or backward. Once I go through this, it works fine to do the entire lawn, but if I take a break (maybe 45 minutes) I'll have to repeat the process.

It's done this for a while now, started last season. It works but is a major pain. The right side works just fine.

Toro Hydraulics Slow