Hello, a few days ago I was driving to work and a white smoke started coming from my dash vents. I was not running heat or defrost at the time, now a few days later the trans is shifting hard, I looked underneath and I can see some evidence of fluid on the outside of pan. Anyone else had this experience?

 

not sure but if you could check these items it would be helpful in making a correct diagnosis. check coolant level and for the radiator leaking at the seams at the side tank connections or rad/heater hoses. check trans dipstick to ensure correct fluid level and for the presence of coolant in trans fluid. this would indicate that the trans lines that run through the radiator have failed. also, i have heard that the heater core is common to fail on these trucks? sound right to anyone? another possibility includes transmission fluid seeping out and onto the exhaust but that would be determined after the level has been checked.