2005 Avensis Verso wagon Auto gears not engaging

[mum_of_3]

I drive a 2005 auto Avensis Verso wagon with 150k on the clock. For 15 months I have had an intermittent problem with the auto trnsmission not selecting the gear. I would slow down to go round a corner or roundabout and as I go to accelerate out of the corner I would put my foot on the accelerator and I would get this loud electronic buzzing sound from the engine and I would have no acceleration. I have to take my foot off the accelerator and re-depress it for the car to go again. The best I can describe the buzzing sound is that it is very much like a spinning flywheel hitting a plastic casing.

The problem intially would happen randomly once every 2-3 months. It first happen only when turning left at a roundabout or corner. Then it occurred going over a particularly high speed hump. It is still mainly only happening when turning left (go figure??) with the occasional right hand corner or on straight drives. But, the problem is getting more frequently with it now happening upto 4 times in a day. Again randomly, some days I have no problems. Recently it happened 8 times within a 36 hour window on a 500km road trip.

There are certain corners near my house that I know it will occur on quite frequently so now I break going into the corner, roll around the corner and then re-engage the accelerator once through the corner. One corner tends to have slighly elevated pavement (perhaps 1cm difference in road levels) compared to the road I am turning from and the that slight bump in road surface can cause the problem. It is almost like it is being knocked from gear but if I was in neutral I wouldn't be getting the buzzing sound.

It recently occurred to my husband whilst trying to accelerate up a hill with the car loaded full. After 15 months he finally heard/felt what I have been describing. But not being technically minded with cars he had no idea either. Obviously there is an issue with the gears engaging.

I have been to 3 different mechanics, one of which was a Toyota Dealer, and no-one can tell me what the problem is. The last one said "sometimes you just have to wait for something to break before we know what to fix". I think this is an expensive way to find out what the problem is.

Any suggestions?

Edited July 1, 2011 by mum_of_3

[avensis20]

As it is now 2013 what was outcome? It suggested a valve body problem.