1999 EB Transmission problem?

I've had a recurring intermittent idle problem that happens every month or so, but usually settles in within 5-10 minutes of driving. Therefore I haven't fixed it. This has gone on for years, I've got 130,000 miles on the odometer.

In scanning the board today, I seem to believe that is the same thing that others have fixed by changing the Idle Control Valve.

However, in the last few days, I've had a more serious problem. It's been over 100 degrees for about a week in Myrtle Beach, SC (if that has anything to do with this). This past Saturday, I started to have what I believe to be transmission problems. While out driving, accelerating at a stop light, the engine revved to about 12000 or so before it would engage and go forward. When it did, it caught and then ran OK until I came to a stop again.

This repeated itself several times throughout the day and the shift points, as far as RPM's go, were higher than usual. At one time, it wouldn't go into reverse, but eventually did, and then drove fine. I let the car sit until Monday, whereby I drove it to the transmission shop.

On the way there, it drove fine, without any symptoms. They hooked it up to the computer and they said it checked out fine electically. However the idle was OK then.

Eventually the problems I had manifested themselves at the shop and he test drove it and quickly concluded that I needed to have the tranny replaced.

He says since the computer said it was ok electrically, that it has to be mechanical, hence the replacement.

I left it there, then a few hours later drove it to a friend's used lot, where I'm thinking about trading it in. It drove without incident again.

Before I decide what to do, (replace with a used, rebuilt, or trade it on another SUV) is there any chance these things are related, or in anyone's estimation do I have a clear transmission problem. The only reason I ask, is that it seems to me, that a mechanical problem wouldn't come and go like that over the course of a few days and hours.

Thanks in advance, any help would be appreciated.

The only thing that I would be able to tell you is to check the tranny fluid level. Remember it must be running and at operating temps to get a propper reading. When was the last time the filter was changed? It could be plugged not allowing fluid to pump propperly.