Here's the deal, ever since I went through my first mud puddle, my transmission/torque converter has been acting funny.

Whenever I make a 90 degree turn, it will slip in first gear to 3k and then slip back into gear and everything is fine.

Now whenever I drive through like a mud puddle or a flooded street, the real fun begins. I lose reverse, and it won't shift out of 1st (or 2nd I can't tell) unless I rev to 3k, then let off the gas and when it gets to 1500 it will go into 4th gear, and then stay there. So essencially I think I've got one functional gear.

Normally when this happens after an hour it will stop doing it and be fine, with the occasional slipping.

Now it rained for about the second time in a year in California, and a lot of the roads were flooded up and over the curbs. I was driving through these at about 20-30 MPH and making a lot of splash, and then the problem started. Now I figured it would go away in a day, but it has been 3 days and still nothing has changed. I've got a CEL and I'm going to a tranny shop tomorrow to check it out and get the bad news, but what do you guys think? I'm hoping it's just a sensor got shorted or something like that, and not a thing that will cost thousands to fix.

This is the 3rd time this has happened, and it looks like it's not going to fix itsslef :(. And the first time it happened I got the codes checked, and had errors for the reverse engagement, shifting out of 1st, 2nd, 3rd, and overdrive engagement. So 4th gear is the only on that didn't have a code for it. And I had the tranny fluid changed about a month ago. 75k on 5r55e.

How's the fluid now?

It is very possible that fluid contamination, though fixed now, caused considerable damage. Hope you have some money saved up :(

I just checked the fluid. It's barely above the first hole, and it's still red, doesn't look burned or dirty or anything.

How long was the fluid contaminated before it was changed?

Either that or something electronic got wet/fried.

I'm thinking that the electrical harness to the tranny is getting shorted when you drive through the water. Especially if you don't see any evidence of contamination in the ATF.

To make sure that you aren't actually getting water into the tranny, check the vent tube to make sure it is still attached and routed above water level.

If the vent tube is ok, I would start looking at the electrical connector feeding the tranny and/or damage to the harness leading to it.

I had the fluid changed about less than 24 hours after I had the problem the first time. Tomorrow i'm going to take a look underneath to see if there is any noticable damage.