I have a 99 powerstoke with 303,000 miles on original transmission. In last couple of weeks it has developed a condition where it pumps out fluid from the overflow when backing up under a load (light or heavy). The first time it did it, I thought I had a cooling problem. The A/C condensor was bent shut due to powerwasher, so I changed it out hoping to get more air to the cooler. At this time I changed filter and fluid. There appeared to be no problem with the fluid. There is no problem in how the trans shifts and it only does this in reverse.

any thoughts?

 

If you have a 4X4 use low range. It greatly reduces the strain on the torque converter which is generating all the heat during those reverse maneuvers.

 

I do use low range when I have a loaded trailer, but it does then also. I am thinking maybe a clogged cooling line or damaged TC.

 

Buck, I have a friend that works at one of the big dealerships. He tells me that everytime they get a transmission for warranty replacment; Ford requires that they replace the transmission cooler regardless of reason of failure. This said, and given the number of miles you've got on the transmission. I'd be willing to say that you've probably got either a plugged line going to the cooler or, a plugged up cooler. That's where I'd start looking anyway. If you've got something shredding behind the oil sump filter; those particals will accumulate in the cooler unless you've got a filter in the line going to it. All the hot oil going to the cooler is unfiltered until it is returned to the pan to be picked up again by the sump filter.