I have a 95 F-350 crew cab dually. I had my 8 foot camper on it, and was flat towing my Jeep cj-5 behind it. I always drive it with the overdrive off while towing and hauling, but according to the dealer book for the 90 ford, it says to drive with the overdrive on while towing (?). We were in slow traffic when i noticed the off light for the overdrive was blinking. When we noticed smoke pouring out the back, I immediatly pulled over, and Auto trans fluid was pouring out all over the shoulder. We were able to go and get more fliud and drove off the highway. After getting it off of the side of the road, I could see some fluid had come off from the top (vent), but some looked like it came out of the plug that is on the bellhousing under the torque converter. I accesed the computer codes and all it showed was that it had detected hot coolant. I plan on adding a much bigger cooler and flushing out as much fluid as i can, and replacing the filter. It still seems to shift fine (I have to take the camper off to check the overdrive out). I know I did not have it overloaded, but does anyone have an idea why this did it? I had the fluid changed last year, before camping season, and have only put 6000 miles on it since last year.

 

Towing in OD will not harm a '95 E4OD tranny. We do it all the time with our '95 F250 pulling a 30' 5er. The only time you really need to lock out OD is if the tranny is 'hunting' between 3rd and OD.

Since you were in stop and go traffic, my best guess is the stock cooler wasn't helping at all and the fluid just got way too hot. You should take the truck to a tranny service shop and have them inspect it. At extreme temperatures, like what you described, transmission parts fail.

Anything over 200 degrees SUSTAINED temperature, and you need to start doing some checking or consider purchasing a cooler.

215 will not hurt anything as long as it peaks and falls. 230 is the absolute MAXIMUM temperature the transmission should run without changing the fluid as o-rings and seals are taking abuse at these temperatures.

Normal adequate operating ranges with a sufficient cooler are 145-195-200 degrees depending on load, outside temperature and terrain. If you never get above 200 degrees, your doing just fine with no problems.

And as an addition, YES, I would definately use either at least a synthetic blend, or FULL synthetic fluid in the transmission as this will make a difference in temperature and lubrication.

Rich

 

dustym,

Your radiator transmission cooler may be leaking water into the transmission fluid. Have your radiator and cooler, pressure tested at a radiator shop.

Lube oil or transmission fluid will foam if it's contaminated with water. Water vaporizes at 212*F. (Less at high elevation). The rapid expansion of the water into steam causes the lubricant to foam over. The bubble point of most lubricants is over 400*F.

Like Rich said, the slow traffic may have caused your transmission fluid to get hotter than normal. But I doubt it got hot enough to foam, unless it was contaminated with water.

 

Thanks for the info.
It doesnt look like my transmission cooler lines run into the radaitor. I will be working on it tonight, so ill be checking that out.

 

Hey Rich,

Do you have a tranny temp guage on your truck? I'm planning on putting one on soon and I'm not sure if I want to go electric, it looks like there is a plug at the top of the tranny (E4OD) to put the sender in, or with a mechanical and splice the line into the cooler.

I have done both OD and non OD towing and it's hard to judge what is right without the guages. I do have a vacuum guage and the engine appears to be much more fuel efficient in 3rd, especially at 55. However at 70 I don't like the high revs and usually switch to OD, and downshift on steep hills at keep it at 65.

Just curious what you are doing? By the way if anyone does lots of towing a vacuum guage is very nice to have to see how much power you have in reserve.

Joey

 

Yes, I do have a gauge installed. I am using the electrical gauge Banks sells. I placed the sender in the service port which is on the driver's side right in front of the linkage. I mounted the gauge in the cab using a single A-Pillar mount.

We just got back from a trip where we pulled our 11,000 pound 5er up to 9,000 ft. Well other than a slow climb from 5,000 to 9,000 (the climb is 4,000 ft in 14 miles), the truck did great! We did have to pull over once and let the tranny cool down when it reached 240 degrees, we will be servicing the tranny soon because of this high temperature. And yes I have dual tranny coolers too, the stock and then a Hayden 670.

Rich

 

Your problem might have been cause by the constant slip of the torque converter in OD off where as in OD there is no slip and the fluid wont be heating up.