98 Jetta GL Auto Trans problem

I work on old aircooled VWs, not watercooled and my wife drives a 98 Jetta GL with in auto transmission. The problem is when the car tries to get up to speed. The transmission does not change gears. It would go all the way up to almost 5Krpm before it goes "oh...I need to change gears!". Any incline and this car will never change gears. Even on freeways it just stays above or on 4k rpms. It just does not change gears and I could just see here cracking the block and blowing a piston right through the case! I have heard of this problem on the web and have also heard that vw AUTO trans suck. What can I do to fix this issue? And she will not drive a stick so a convertion is out of the question.

auto trannys do suck, with a capitol S i have to get my rebuilt of swap to 5spd....