Understandable. Making a decision based on a long-distance diagnosis is never easy.
You'd have to ask of course, but the VX.info member Cobrajet appears to live about an hour away from your listed location (the Arlington area), and from what I remember, he's no stranger to doing some of his own vehicle repair work. If it were me in your situation, I'd try getting in contact with him (or any other VX members you can find in your area by searching the site member list) to see if you could find someone willing to make a trip sometime to change your trans fluid and filter to see if it makes a difference. If I lived closer I'd do it.
A couple of other things that could be checked are the wiring harness connections coming from the passenger side rear area of the transmission itself, and the transmission gear select switch on the drivers side of the trans. The connectors on the passenger side of the trans are well known to allow moisture inside and cause all sorts of erratic electrical inputs to the trans controller as well as transmission malfunctioning. And the transmission gear select switch has similarly been known to be a part that commonly fails/rusts, in it's case due to heat and moisture given it's proximity to the exhaust system.
I had water getting into the passenger side trans electrical connector once during a heavy rain and it had my transmission jumping gears and my TOD display looking like a pinball machine. It'd be a shame if it was something relatively simple (Vehicross-wise) like that and a trans rebuild/replacement didn't solve the issue. And to head off any problem with my gear select switch, I wrapped my exhaust in the area with high-temp exhaust wrap.
Then again, getting a second opinion ALWAYS comes to my mind when anyone starts talking about a high-dollar repair estimate, but maybe I've just seen too many of those investigative journalism shows featuring shady repair shops "creating" issues on vehicles just so they can charge their customers more.
To search the site member list:
- Select the "Forum" tab.
- Select the "Community" tab.
- Select "Member List" from the drop down menu.
- Select "Search Members" over on the right of the page.
- Select "Advanced Search".
- Then narrow the search by State, etc. (I found Cobrajet by searching in VA then clicking on the "Last visit" tab to further narrow the search to the more recent site visitors.)