I have an 89 Bronco II with the A4LD transmission. The vehicle moves in every gear except OD. The fluid level is correct and looks good. I dropped the pan a while ago and the fluid actually looked really good to my surprise. I can shift manually through 1st, 2nd and drive and the vehicle will react. But when I put the transmission into overdrive it just revs and the vehicle barely wants to move. Could there be something electronic causing this, or is the transmission just shot? It would be a shame because it seems to move well in the other gears. Doesn't seem to slip at all.

Thanks

 

Anybody have any ideas?