automatic gearbox problem

asilvah

I Have a Astra G 2001.

I recently had a problem with the transmission. While in Drive, once you free the break pedal, engine speeds at 1500 rpm and car starts to change gears up to 4th relation. So car gets quickly at 60Km/hr. Applying breaks at this point will slow down the car but slowly because its accelerated. Safest way is to switch to neutral and engone runs down to 700 rpm.
Same problem appears with Reverse selected.

I took it to a garage and no error code comes up from ECU.

The mechanic told me that It can be 2 things:

1.- Damaged transmission
2.- Damaged transmission ECU (reason way is not reporting error code)
3.- Both. Due to a Transmission ECU problem, the transmission got damaged too

What is your opinion about this?

alfonso

vocky

if the engine revs on it's own then it sounds like an air leak on the inlet manifold intake system

but I know when you select a gear (on an autobox) the engine revs should increase slightly, it might be the selector switch on the gearbox is not adjusted correctly