I hate to do it but I have a 50 miles 1 way 50 Mile back trip I need to take tomorrow&Im yet to go pick up my Trans cooler so right now it's but passed, I just got this truck legal friday.So will it hurt anything if I do it this 1 time? I would usually skip but I restore older cars/hotrods...bodywork for a living & a fella has I belive a 2007 maybe 08 4th long bed with the 6.7 Cummins he wants me to come see IF u want it..which I already know I do lol but I have to go look@the work he has for me to do. SO...am I gonna be ok?

 

You'd be okay around town but I wouldn't drive that distance without the cooler.
However I installed a new trans cooler and thermostatic valve, and every time I check the temps with my infrared gun the temps are 120 to 140 degrees, not even hot enough to open the thremo valve to flow thru the cooler. How are the temps there in Missouri? If not very cold I would not make that trip.

Edit, You have the Cummins, lot more weight and torque there than my 1/2 ton V8. Don't do it.

 

You could grab an infrared thermometer from HF, they have a pocket one for a pretty good price that reads to around 230 F, and point at the trans pan every few miles and see how it's doing. If it gets upwards of 200 then I would pull over and let it cool down, but I am guessing it will be fine as long as you aren't going over a mountain pass or something.

 

No trans cooler at all? No. Don't do it. If you still have the cooler in the radiator though, just don't tow anything, and you will be fine.