My 83 chevy has a built TH700r4 in it, and after I burnt out the stock one, I put in a temp gauge with a very large auxilary cooler. Sometimes when I tow up hills, or am running with a heavy load up a hill, I can still make it heat up pretty good, if I stay in the gas hard. I was wondering what all of you had for opinions as for the top operating temperature I should keep for a sustained period. Right now when it hits about 180 I've been backing off a bit. I never tow in overdrive. The worst I've noticed was about 225 degrees after flying up a mountain pass, mad at the girlfriend about something, and not paying attention. Thanks for the input.