e4od shifting problem want to shift from drive or 2 at low speed 10 mph to 1

What is your question?

This is what I have done, I pulled out of a 1992 ford motorhome a good working e4od transmission that worked great. Had to tear down to replace the out put shaft to the short out put shaft for 1994 F-250 4x4 put it back together the same as I took it apart. Put it back in the truck took it for a short test drive goes in and out of forward and reverse smooth but at say 10 mph let off the gas peddle it shifts back to 1 gear on flat ground in drive or 2 gear. I don't no if I missed something in the valve body or did not get some thing in place right or could it be electrical or a computer problem

What makes this problem better or worse?

nothing at this point

How long has your 1994 Ford F-250 had this problem?

from the time I put it back in the truck