GU1 Auto Trans not engaging

[twisty]

G'day all,

Well, the auto (r03) scared the willies out of me yesterday! 80km/h on cruise and the auto disengaged. Engine revved to 3k and climbing before I turned the cruise off. Give it some revs with the right foot and away we go again. wtf? Then, 5km later coasting down a hill at 70kmh (3rd gear, OD off) and engine revs drop to idle, huh, apply right foot and ... nothing. Hazard lights on and find a safe place to stop. No gear is engaging, not even park, engine idles happily with new fuel pump. Turn it off and contemplate my situation while I roll a smoke. Restart and we have gears again. hhmmm ... Another couple of k's down the road coasting and same again ...

Now I was intending getting dirty in the local mountains but I've changed my mind and I'm heading home. Climbing back up the valley and same problem again but this time under load. Nurse it home and get every green light

So this morning I go for a test drive. No problems.

Yes, I've checked the ATF before and after the problem. It's a honey colour and hard to see on the dip stick. I checked it in "P" and "R". It looks over full to me? Put 500ml of castrol transmax multi (red) in anyway and check again. It still looks overfull but seems to drive better (it may be my wishful thinking). Got me buggered

Last professional check and top up was 3k ago. We're going back to the mechanic this week for a better look.

Any ideas, suggestions or words of wisdom greatly appreciated.

edit. AT eventually dies and is now replaced with Wholesale Auto Extreme.