I pulled a boat home (about 200 miles) from Lake Havasu to Phoenix in 115 temps a few days ago. My truck is a 1996 Dodge Cumminjs 12 valve with 120K mileage (bought it new).Started the trip at 8AM and got home around noon. I only stopped once at a rest stop for 5 minutes and let it idle. Upon getting restarted, I thought I could feel some softness in the transmission starting off so I immediately shifted to OD lockout opened the windows and turned on the heater full blast. I drove home at 55mph watching the trans temp showing 140 all the way. My trans fluid now looks pretty red and clean.

I haven't had the truck back out yet.

Is it likely I damaged anything? Is just driving around the only true test of the tranny being sound?

Thanks.

 

If the fluid does not smell or look burned i not sure how you could have got it over heated. . Normal tbe heat if from the fluid coupling and not lockup ..i burned mt 47rh up and it would barely moved when it was removed. Mine was a 95 with about 215k i think. Its still burned up as i gave it away ..i now have a g56 in from of the transfer case... if you want you could drop pan and change the fluid and filter . I ran 10wt hydraulic oil for 20 years when i believe i lost the clutch in the convertor and i kept driving it for a ciuple more days. I assumed that took out the rear support when the fluid come back in ....i regretted buying automatic after i got it ..if i had your truck i inspect the cooling lines as thet tend to rube each other and can cause a leak . I always went to neutral after i started it to charge the convertor..you can also check the oil pressure with a gauge to see if you have proper oil pressre. Good luck

 

140 degrees is NO PROBLEM for the trans. I've got 486,xxx on my truck and 380,xxx on my ATS trans rebuild. No problems ever. Hottest trans temp I've ever seen is 165 in summer stop and go, in town traffic. As soon as I was able to get up to 40 mph for a bit the temp dropped back down to below 140.