Why is my 2000 Jetta automatic transmission shifting problem?

What is your question?

I have a 2000 VW Jetta, 148,000 miles. The past few weeks the check engine light is on and the car will not shift from first to higher gear until the engine speed reached ~4200 rpm. I suspect there is something amiss with the automatic transmission, and if it is an issue that might be resolved with replacement of the transmission which might be more expensive than the car is worth.