I have a 1998 5.4L Expedition (with factory tow pkg) that I use to tow a boat (approx 3000 pounds). I purchased the Exped. used with about 45K on it and had to replace the transmission with a rebuilt after only 54K. I now have 91,000 on my Exped. Last week while on a trip to KY pulling my boat I noticed that the Transmission seemed to lack power going up hills and seemed to rev higher between 2-3rd gear. It seems a lot like the issues I had before I replaced the 1st trany. Now that I am back from Vacation I had it checked out but... the shop said it did not have any codes set or did not notice anything wrong. Of course in town without a boat it seems fine to me too. My real question is how durable is the 98' E4OD for towing. I try to tow with the OD off, but my boat is only 3,000 pounds and I am wondering if the trany just is not built good enough for towing. I love my truck but can't replace the trany every couple of years. Please let me know your thoughts on the quality of the 1998 E4OD.

Don

 

There are guys on this forum that are really familiar with these trannies and know the inner workings of them. I'm sure they can get more in depth on them. I bought my 1st Ford which is a 1997 Expy with the factory tow pkg. Before I bought it I called many tranny shops in my area to ask about the E40D because I tow a 5,600 lb trailer and will load another 400lbs into the truck. They all told me it was very strong with extremely large clutches. Most all of them did say that Ford programs it to shift soft in our application for comfort. This leads to more heat and less durability. There are differing opinions on this site about how to firm up the shifts but I installed a Banks Trans-Command and love it. It firms up the shifts based on load on the vehicle so the shifts aren't firm all the time. Only when they need to be. I pulled this trailer 3 or so times before the Trans-Command and thought it pulled well but I did notice the mushy 2-3 shift which is apparently a common trait. I have not had a problem with mine yet with 102,000 miles. I bought it with 83,000 or so miles. I run Amsoil Universal ATF in the tranny which lowered the tranny temp 10-15 degrees just after changing the pan once. I now have it totally Amsoil and it is still 15-20 degrees cooler than with the fluid that was in there when I bought it.
A friend of mine just changed the fluid out of his newer F-250 with the E40D to Amsoil because he was afraid the mushy shifts were generating too much heat. He changed it all at once and immediately noticed a better shifting transmission. He then decided to change the fluid in his Chevy over also.
I also tow with mine in OD and let the speed drop a bit on hills rather than run it in 3rd and maintain a constant speed all the time. I believe and maybe somebody can verify it but in 3rd the torque converter slips which generates tons of heat. In OD the torque converter is locked up most of the time so it doesn't generate as much heat. When you hear about trucks spewing tranny fluid while towing each time I've heard of it the person was running in 3rd. I always run in OD and haven't had a problem.
I would not worry about the tranny. I think it's pretty strong.