What gears are in your 3/4 tons. I when through 4 TH350s in 4 years with a Stock 427 TD and 4.56 gears. If you run the TH350 you need 5.13 gears that MIGHT make the Trans last longer. The last one I took a part to see what happend and ALL the hard internals where broke. Wish I had taken a picture now.