Driving home from work yesterday in a torrential downpour. Actually the most rain ever recorded in the month of August here. Luckily it happened about 3 blocks from my house but the dreaded 'gearbox fault' showed up again. The history on this thing is the first time, in the rain, on the freeway and I get the code. I freak and into the Dealership, they clear it and I'm fine...no cost. Second time, I bring it back and they replace the TCM, water test the car, tell me there is a really tiny leak with the windshield that was not the original windshield and I should get it re and re'd. But I didn't, then it happened once more but the whole summer it's been fine. But it went from 75 degrees down to 60 yesterday add in the rain and the TCM got wet. Drove it home, let it sit, this morning there is no rain so I opened the sunroof a bit , cranked the heat to max and shut the dorrs and left it for 20 minutes. Drove to work (25 miles) and it seems fine.
THis weekend I'm going to do the trick the dealer told me about. You pull the TCM, unplug it, get a small plastic bag and cut a whole in the bottom of it, run the wires through the hole then seal it around the wires making it water tight. Put the TCM in the bag and plug it in but the open part of the bag is at the bottom so it acts like an umbrella for the TCM. I'll take pictures and post them so you see what I mean, maybe it will stop some of the where is the TCM threads.
I'm away for 2 weeks later this month so I'm leaving the car with a shop to replace the windshield that mysteriously got a crack in it.... I'll let you know how it goes.

 

Do you think you could take a pic of the TCM and put it up?
Ive been looking for it for the past like week and still have nothing... i belive i found it though, but there is a little gray box mounted on top of it or something like that.

 

Hey SIdewalkman,
I've been having the exact same issue, and would also appreciate it if you could post a pic or email me one of the TCM. Thanks!

 

Charm,

You are correct, that is the TCM. My 2002 has a swinging latch to hold the connector in. It is tucked away in the dash, near the fuses. Below is a picture of the TCM with the cover taken off.

 

Never got to the TCM since I decided to get the windshield replaced. Cost me a couple of hundred for the deductable but it had a crack so might as well.

The dealer told me that the small amount of water had to be coming from the windshield since they had it in the spray booth for 3 hours and nothing. Problem only happens in the rain too.

But I felt under the carpet and it might be a tad moist but certainly not wet. We'll see, I'm in the rain capital of the world so if it's not raining when I pick up the car it likely will be within 5 minutes. Hopefully it solves another problem which was the right side of the heated windshield never worked, the WS was replaced right before I got the car so likely the guys didn't plug in one side, the mirror electric on the mirror didn't work either.

I'll let you know.

 

Sweet thanks Tpro123, you just answered my main question.
Thanks for the picture i really appreciate it.

good luck with that sidewalkman, tell us if it helped.

 

So got the car back from the Glass place yesterday. He found an air pocket, he said it's likely the place that did the windshield prior had a bubble in the sealer that popped leaving a void. The void was on the drivers side and the water travelled down and collected right below where the VIN number is and was dripping down into the drivers compartment. Probably that was following the wires down into the TCM. I'm not going to do anything more for now and see if I get gearbox faults again.

And he also found really bad corrosion on the passengers side plug for the heaters in the windshield. No fog on the windshield this morning so....

 

Sidewalkman- That's interesting, because my windshield is cracked too. Wonder if that's where it's coming from then. Keep us posted on any updates please, my trans has been stuck in 4th gear in "limp home" mode since a rainstorm last week. Thanks.

Tpro- When I click on your pic of the TCM it says that I don't have permission to access it, do you know why that is?

 

Commonly the water actually runs down the hood release cable and gets into the car. It's not enough water to get your carpet wet, but enough to screw up the TCM. For anyone that has repeated problems with the TCM getting wet I found that you can take the TCM from its mounting location and wire tire to the big harness that runs along the the width of the dash. This puts the TCM up high and the water can't get to it.