You're not checking for Water. You are checking for the past presence of Water...which means corrosion. Pull up the carpet on the passenger side near the door and look at the wire connectors. When you reported that your mechanic needed to reset the computer after the Brake Switch install I was suspect. I'd never heard of any kind of software flash being necessary for that. The fact that you have actual physical symptoms (like the 4k RPMs at 50 mph) is troubling to me.

You may need to bite the bullet and go to a LR Service Dept. People disparage the "stealership," but mine treats me rather well. Maybe yours will too.

 

I was sort of inching towards the same conclusion... to the dealership.

 

To echo sentiments of fellow posters;

Yes - you're not checking for water. You're checking for corrosion. Did the dude abide or did the dude ignore and not dissassemble the center console near the shifter and inspect all Harnesses ?

And now that you're mentioning the transmission sleeve, I go back to my other comment; to replace that sleeve you need to drop the pan... I believe. So..

1. Struggling to believe your local guy did that. It's not exactly a small job.

2. If he didn't, it means you're leaking tranny fluid and you're exhibiting tell-tale signs of low tranny fluid.