We have a 2001 super duty 7.3 with auto trans. Saturday while hauling balage on goose neck out of field it began leaking fluid profusely out hole in pan. The driver did not know until the truck stopped moving. This is all slow hauling on farm; no highway at all at speeds below 20 mph in four wheel drive low range. we pulled truck to barn and added 17 quarts of fluid, started truck to try and find problem. Now we have no leaks and truck performs as if nothing happened. I assume it is a heat problem but am puzzled as we try to reduce torque and slippage by operating in low range. Has anyone had this problem and did it cause permanent damage?

 

Welcome to FTE, Mary.

I'm not understanding what you mean by, leaking from hole in pan?

Is there a hole in the pan or are you looking at the inspection plate between the trans and engine?

Does sound like you overheated the fluid and it started leaking out of the front seal. When the fluid gets hot, it softens this seal and allows fluid to leak out. When the fluid cools, the seal goes back to original shape. Adding 17 quarts is almost all the fluid.

I would install a 6.0 trans cooler for better cooling. I have a Tru-cooler on my truck and it's doing a fine job of cooling the fluid.

Also, make sure the coolers on your truck are not plugged. You have one going into the bottom of the radiator then to a small cooler on the outside.

 

Also in addition to what Miller feed said a transmission temp gauge would be very beneficial as well to moniter those temps so it doesnt happen again.

 

x2 with both suggestions above. Clay Riffraffdiesel.com has all the parts you need.

 

Yep, what they said...... when crawling along there just isn't enough air moving through the small factory trans cooling system to overcome the heat generated. The seal will allow fluid to leak when it gets hot and soft. Some have been lucky and the seal be OK and stay OK. Some have experienced leaks later due to seal breakdown. Keep a close watch on things and make sure your seal "healed" and stays that way. I sprung for a cooler after the same issue backing a 5th wheel to long ! I also did a rebuild on the tranny at the same time. It was getting tired and I didn't want to have to do it on the road somewhere !

Good luck and keep us posted.

 

Thanks all. The truck still shows no ill effects from overheating. We will add a cooler and a gauge and hope for the best. When we do add the cooler, should we get a larger one and delete the factory unit, or is it better to place them in series?

 

The best way is to replace the factory cooler with a cooler from a 6.0L (2003-2007) truck.