After the car has warmed up, when I am driving the automatic transmission 1997 6cyl 4wd at around 45mph or higher, there is a loud clunking and lurching coming from the trans. It happens when I take my foot off the gas and coast, and then depress back the gas to re-engage the trans from coasting. the engine runs fine. I was hoping this could be something other than the trans, like a sensor or something. There is no slippage of the trans in any gear. 135,000 miles.