Automatic Transmission problems of the 1998 Chevrolet 1500

I have a Chevrolet 1500 conversion van. Transmition unable to go into any gear. I was in lynchbury, va. Had to be towed. This incident occurred 11/23/01. Had to have transmition rebuilt. I was told that the manufacturer had done some update to the model transmition in my van. 06/01/04 transmition slipping. Had to have transmition rebuilt again. In 21/2 years I have spent $4,500. On repairs to transmition in my van. It is obvious that that transmition in my van is not compatable with the wiegh of the vehicle, and the manufacturer knew this. I didnot get 40000 miles before having transmition rebuilt again.

While driving vehicle intermittently will not go into the passing gear. Dealer can not identify the problem.