Transmission Slip Out Of Gear problems of the 1998 GMC Sonoma

Transmission is slipping out of gear and drops into neutral for 1-2 seconds, and then goes back into gear, causing a revving in engine. Consumer contacted dealer in July 2000, but could not determine cause. Currently, consumer is having problems with transmission sticking in gear. Same dealer claims transmission needs to be replaced. Consumer states stuck gear resulted in an engine brake condition in a reduced speed zone where vehicle speed is suddenly reduced with no brake lights on, consumer found TSB 99-07-30-005 regarding this problem and stated the recommendation was to replace the valve body assembly, however this was not been done until the valve body assembly failed which caused 3rd gear to lock on the highway, consume rwants gm to take responsibility for this problem.