Swmpbgy1 wrote:
PUCampin wrote:
I know you said it is an 01, but double check the off chance and see if the transmission cooling lines have the pass through in the bottom of the radiator. For a short time Ford decided to delete this and rely strictly on the oil air heat exchanger, which does not work well when going slow pulling a hill or backing up! I believe in mid 2000 model year they reverted back, but it is worth a quick look. If you do not have the pass through, you will need a radiator for a later year that has the pass through.
PUCampin:
Could you please elaborate on this a little more??? I have a 2000 Excursion 7.3l that when I tow will puke tranny fluid while backing into a camping site. What exactly am I looking for? Do you have any pics of the set up that you are describing?
Swampbgy1
Most vehicles with an automatic transmission use a water/oil heat exchanger (transmission oil flows through tubes immersed in coolant) in the bottom of the radiator to cool the transmission fluid. This type of heat exchanger is quite effective and works as long as the engine is running whether or not the vehicle is moving. For most vehicles this is all the transmission cooling necessary.
HD vehicles that are designed to tow often have a secondary cooler that looks like a small radiator. This is an oil air heat exchanger. These are not as effective as the oil water cooler, and they only work when a good deal of air is flowing over them like when the vehicle is moving.
Between build dates 1/5/98 and 2/6/2000 for SD and Excursion, someone at Ford decided to remove the oil/water exchanger in the radiator leaving ONLY the oil air heat exchanger to cool the transmission. Since this only works well with air flowing, guess when it does not work well. Driving slow on hilly or windy roads, and backing and manuvering. Since there is no oil/water exchanger to cool during this type of driving, and backing is a lot of slipping the fluid heats up FAST. If it was warm from a hard pull already, this happens even faster.
The fluid can then come out a breather, or it can leak past the input shaft seal and drip from the bell housing. Once cool the seal will seal again and you won't continue to leak. However, the number of times the seal will reseal is limited before it will continue to leak.
After 2/6/2000 Ford went back to including the oil/water exchanger.
I do not have pictures, but it is easy to tell. Follow your transmission line from the transmission to the front of the engine. It will eith go into the bottom of the radiator out and into a second cooler then back to the transmission, or it will go just through the small second cooler and not into the bottom of the radiator.
If you do not have the oil/water exchanger, the best thing to do is replace the radiator with a newer one that has the exchanger. You can also swap the small stock air/oil cooler with one from a 6.0 for additional cooling.
The SD and Excursion were not the only vehicles Ford did this on. My 2004 Explorer V8 was the same. No oil/water exchanger in the radiator, just a small stacked plate oil/air cooler sandwitched between the radiator and condensor, mounted down low below the influance of the engine fan and shroud (meaning the only time there was much airflow over it was when the veghicle was moving). I pulled my sig TT with the 04 Explorer up and down mountains, and discovered this the hard way. It did ok, but like you would leak fluid after arriving at a site or home while backing into place. The next morning it was fine.
I took it to a dealer and they wanted to remove and inspect the trans for $800 just to attempt to troubleshoot the issue. I declined and did some research. That is how I found out that when too hot, the fluid can leak past the shaft seal until it cools. I ended up trading the Explorer in due to my family outgrowing it before I could do anything about the cooling
The member Mark Kovalsky (who posted in this thread) is a Ford transmission expert, and is who I learned this from. He can tell you what radiator you will need and what steps you can take to get the most of your transmission.
Hope this helps, you are welcome to PM me too.
Daniel
