2002 Volks Jetta - Rough shifting automatic?

[mccannam]

We have a problem with our 2002 Jetta transmission. It is automatic and the down shift from 2nd to 1st not smooth. Sometimes it actually makes a good thump. This started around 20,000kms and still continues today at 52,000kms. It is starting to occur when accelerating as well, from 1st into 2nd.

We have taken it to the dealer and explained the problem and he has done some 'software' changes, but it still happens.

Does anyone have any ideas about this? Anyone ever heard of it?

thanks, Mark