Transmission issue after Engine bay cleaning

The day started off by going to work. It's a 5 mile drive. No issues with the transmission at all. Go home for lunch and to let the dog out. No issues. Drive back to work.. No issues! At the end of the day I decide to go and wash the truck. I've sprayed the engine bay before and no issues. So I did it again. This is when the issue started. All of a sudden the transmission is acting up. Put it in drive and it seems to want to stay in 1st. No up-shifting. In fact, it feels like it goes from 1st to neutral and then back again. It cant figure out where it wants to be. I limp home and start to think what the heck is going on. How can it be fine the whole day and all of a sudden its jacked up?

I have done the following. I made it home and fired up the air compressor and took out all of the plugs to make sure there was no water in them. All is clear. I check the transmission fluid. All good. The kick down cable is operating correctly as well... I'm lost! I work for a Toyota dealership and my mechanic is even stumped!! Manual shifting from L to 2nd to D does not work. From the chain of events, I really feel that this is something small and not the actual transmission. Any ideas from any of you?

 

Take it to a different mechanic and get another opinion. I lost hope in my dealership when they charged me twice(400$ Each time) to do valve cover gaskets.lol
They did the gasket but didn’t change the grommets that come with the kit..

 

How old is your vehicle? I get the impression you spray/wash the engine bay sort of often not a good thing in my opinion. I'm no mechanic just my .02 No need to invite issues introducing the water to the engine bay.

 

Yeah, I do this all the time from my first Toyota 4X4 in 1980. My vehicles all have clean engine compartments like they are brand new. You can change a plug or an air filter in a white shirt. It’s no big deal.
Your transmission problem is not related to water. Cause and effect can be misleading. Good luck! BTW, a good transmission guy can diagnose this in a heartbeat, it doesn’t sound like they know how to do this at your dealership though

 

Is the fluid level correct? You wanna check it idling, AT fluid temp between 158-163f.