got a 97 expedition 4x4 with 180,000 and its never had even the smallest problem till now. last summer i towed our 21" ski boat to the lake with it in arkansas and it struggled a lil bit to get up some of the mountains but the check engine light came on and stayed on for about a week. did the same thing this summer but it stayed on for about a month now. plugged a computer to it at my shop and it gave me some transmission code but not sure what it was. hint: only right after i tow a boat or put it in four wheel drive will it make a weird noise, like a diesel almost, and no its not the muffler heat shield. is my tranny bout to take a crap or is it somethin simple like a valve stickin? please help.

 

If you can get the stored code and post it up we can have a better idea of where to start.

Darrin