History transmission was new and has 4000mi in 10 years put on it. not left to sit so much as just not driven out of the neighborhood but would sit for 2-3mo at a time. lifted 1991 4x4 explorer sport with 4:10 gears.possible problem was always there since rebuild but trying to make it a daily driver. When taking off in OD it feels like it is in to high of a gear and dropping it into D you can feel it drop down even when still in first. the vehicle feels like its towing the whole time and always in to high of a gear with low RPM. If taking off in D the vehicle drives normally and has power once 50 or so mph it can be put into OD and continues to drive normally and even down shifts to pass just fine. once stopped it must be put into D or it is sluggish on take off. occasionally when stopping at about 10-15mph a clunk like a down shift or it being forced out of lock up can be heard and felt through the drive line. if a slow gradual stop it usually doesn't do it. I have tested everything electrically and the overdrive is only commanded on when it should be. Im thinking possibly the OD solenoid is bypassing and partly engaging the lock up or something in the valve body. considering replacing valve body and seeing what happens. any ideas or thoughts are appreciated.