I just bought a 1999 Silverado 4x2 with 99,000 miles on it . Purchased from the original owner.
I have all the service records from him. He changed the transmission fluid at 50,000 miles. I will also be changing the fluid at 99,000 miles and putting a bigger transmission cooler on at the same time. I plan on doing a complete flush including the TC. I would like to put a transmission temp sender in the transmission line some place. I will have to research this.
GREAT reading here.