99 Trans Overheating

[autobuyer24]

Ive got a 99 Dodge 2500HD with trans overheating problem. the truck only has 39000 miles on it. Fromt what I read this seems to be a common problem. The manual say the truck is capable of towing up to 10,000lbs. A couple of weeks ago I pulled a 94 Ford explorer on my car hauler back to Albany, GA fron Jacksonville, Fl without a single problem. I went to North Carolina and picked up a 99 S-10 Blazer 4x4 and transmission starting overheating about halfway back it did it 3 times. Of course I was in the Mountains. as long as I didnt stop it was fine, but if I stopped at red light the trans temp light would come on when I take off.. The explorer weighed 4700lbs and the Blazer weighs 6200lbs. When I got back I had the trans flushed and filter changed. Truck did fine for about 2 weeks then I wwas cruisin around town runnin erands when the truck kicked out of overdrive on a open road running about 55mph. I wasnt even pulling a load. I got home and could smell the fluid getting hot. I pulled the stick out and the fluid had got burnt within 2 weeks of the service. So I got to looking and found that the truck is not equipped with a trans cooler. This is an HD model 2500 why in the world is there not a trans cooler. So I went to carquest and bought the biggest trans cooler I could find. I got one for motorhomes towing up to 25,000lbs. This thing is huge. I bypassed the radiator and went straight to the cooler and then had it serviced again. New fluid and filter again. That was a week ago. So far no problems. Im going to install a trans temp gauge. I checked the temperature with my temp reader after I ran pretty hard to get it good and hot and found the temperature below 180 degrees. at idle sitting still in drive it went up to 188 and no higher. I havent pulled a heavy load to see what its made of. Im pretty sure it will be fine. My question is: Is what I did a good idea? Is there anything else I can do? what about a trans fan? If I ran the cooler in series will it help? But Ive always found a trans runs cooler when the radiator is bypassed. The cooler I got should make up for the difference, right? The cooler is abolut 12 inches wide and 15 inches long and about 1-3/4 thick. I know if the temp. gets a little high it will kick out of overdrive to keep from buring overdrive up. It did once when I started pulling the blazer, I just forgot to take it out of OD, but when the trans cooled down it went back into OD at about 70-75mph. Does anyone have the same problem I do and what did you do solve it?

[scoutinkeith]

sounds like you're on the right track with the larger cooler, and temp guage. you might also want to look into removing the check ball in the cooler line. it's "supposed" to keep fluid from draining back, so that the torque converter stays full when the truck is turned off. what it really dose is, get cloged up and restrict the flow of trans fluid to the cooler. the only thing to note about removing that check ball is that when you start the truck first thing in the morning, you may need to put the trans in "N" for a few seconds to get the torque convertor full of fluid before puting it in gear.

[fredjacksonsan]

Cooler is better!

why they wouldn't have a trans cooler stock on a HD pickup.

[2000mudder]

i read somewhere that dodge transmitions are supposed to have the bands adjusted every so often. that would also cause trans fluid to get hot due to slippage of clutches!!! you did the right thing by installing a cooler, just hope it's not too late! i too can't believe they didn't put a cooler on it from factory unless it dosen't have a factory tow package.

[troy1]

The cooler is going in the right direction for sure. A deeper trans pan with the fins on it would help so too (more fluid plus the fins to draw the heat out). Checkball removal would be a good thing to if you don’t mind the delayed engagement in the mornings.

[wafrederick]

There is another thing to check,the rubber hose part of the bottom transmission line towards the radatior.There is a nylon checkball in that line.Get rid of the checkball,it melts right up and will burn the transmisson right up.take a long #2 phillips screwdriver through that rubber hose part and tap on it.That checkball should pop out with a spring