We recently lost yet another 4R100 transmission. And, have lost numerous E4OD in a miriad of trucks. Here are some things the shop foreman of our dealership told me that you need to know. First, changing oil on regular interval, is critical, as is a large after market cooler on these transmissions. Of the many problems that occur in these trannies, there is one thing that will kill your transmission faster than anything going. Because of Ford's lack of forsight, they did not design either of these two transmissions to circulate fluid when in reverse gear. So, the oil sits in the transmission cooking until you shift into drive. In many scenarios, in our area, you get off the highway pulling your load, in our case a 257B Caterpillar, or Wells cargo enclosed trailer, or even a load of dirt in the F-450. You get to where you are going, and you have to back up. Much of the time, you are backing up a hill to park the trailer. You tranny oil is already hot from working the truck, and you heat it up further by backing up. This is the exact scenario that occured when our 02 F-450 lost it's tranny, with 29,000 miles. It has been the second time this happened. In an ideal world, he said if we could let the truck sit for a few minutes so the fluid would cool before backing, it would add thousands of miles to the life of our transmission. Why in the world Ford chose to design a work truck with a pump that does not circulate in reverse gear is beyond me, but learning the way that causes the least stress on the tranny is what we will need to know in order to keep your truck in service. I asked him then why snow plowers can continue as they do all night long. Think about it...you aren't really unde rload when backing up with your plow, and, since the temperature is usually below 30°, the transmission temp would run close to normal. At present, this truck will probably be sold and we will replace it with a Mack Granite, 33,000GVW that has an 8 speed and a jake brake. that truck will be equipped with a roll off dump body. I firmly believe that by operating a truck just one size over what you really need, many problems will be eliminated. The part I cannot accept, is that an F-450 is obviously a truck used for heavier work than a pick up. Putting a transmission like this in it was clearly a bad choice, and one that we as owners will get stuck with bearing the burden of. This transmission is not fit to run in a Bronco let alone a 10,400 lb truck.