After driving through a mud hole water got into the transmission and now the transmission is stuck in first gear

Got into a mud hole a couple weeks ago, didn't swamp the motor but it was about 3 ½ feet deep and was in it for half an hour while I winched her out. Once I got back on dry ground, it was idling high, misfiring, and when I got back to the road and my speed climbed, it was stuck in first gear. I limped her home about two miles, hosed her down and immediately checked fluids. Definitely water in the transmission but thank God not in the motor. Dropped the pan right then and let it drain. Got the filter and gasket and fluid and put it back together hoping for the best, but it's still in first gear.

I was reading here it could be the TPS (seems unlikely from your experience) so I bought a new one of those, but it didn't fix it. I bought a new solenoid (It's a 30R so it only has 1?) But I couldn't figure out how to get that plate off to get to it, so I abandoned that.

Just hoping for advice on any other things I can try before I putz around to the transmission shop for a currency enema. When I say "that plate", I mean the Valve Body.

Thank you and have a great evening.