Problem with AU2

[macman]

Been driving my sisters AU2 Forte over the last week and have been experieincing problems with the gearbox/gearchages.

Basically before the auto shift to 3rd (when in D) the box is hitting neutral for a second allowing it to free rev (and if you don't let off the revs obvioulsy it 'bangs' into 3rd)

Seems to be happening cold and warm.

You can avoid it by holding it in 2nd and manually changing to 3rd at 2k revs.

Also is shifting into 4th when held in 3rd.

Fluid level is fine.

The car is a I6, with the column auto if it makes any difference.