I have a '05 E-350 5.4L engine with 4R75-E transmission that was bought with about 140,000 miles at the time. Within the first 600 miles of my ownership, the transmission dropped out without warning. I ran the CarFax prior to purchase but there was no mention of installing a remanufactured gearbox. When removed, the same type of label was visible. A few thousand miles later, while registering a Ford Reman'd engine, the rep mentioned that the same chassis had actually replaced the transmission under warranty a few years earlier. The guy who rebuilds transmissions for me said that almost every internal part that could fail he had never seen such a mess. /Long story short, it's not all that uncommon for parts or assemblies to be replaced early under the factory warranty. Without deep access to chassis history through the Ford dealer systems, services like CarFax tend to miss these types of events. Nurture this transfer as recommended, including Mark K's full fluid replacement - you'll thank me later. Mark K fluid exchange

 

A friend recommended me to try CAT Caterpillar ET. I don't know if it is useful. Guys, please give me some advice.