Engine Head Gasket Failure problems of the 1999 Chevrolet K1500

I have been a life-long gm owner. In 1991 I owned a Buick regal and in 1992 I owned a GMC jimmy. By the late 1990's I had owned a '93 blazer and a ?94 c-1500. Never have I had as much trouble collectively with these four vehicles as I have had with my 1999 silverado k-1500. It began in October of 2003 when after only 46,584 miles I had to have the right and left head gaskets replaced due to deterioration of the gaskets, which totaled $989. 47. The life-long mechanic that repaired the head gasket believes that the gm/100,000 mile antifreeze deteriorated the gaskets and therefore replaced it with the time-tested standard green antifreeze. I was willing to overlook this problem but right before christmas of ?04 I had to have the automatic transmission and torque converter completely rebuilt due to the loss of second gear, fourth gear, and reverse for the total cost of $1234. 00. The owner of the transmission shop was able to diagnose the problem initially over the phone because of the numerous other GMC or Chevrolet transmissions he has had to overhaul. I have the work -order/receipts for both jobs completed.