Sounds like you're talking about ESOF, yes you really need to be moving forward for the hubs to properly engage. IIRC, up to around 45-50MPH.
Jay /ubbthreads/images/graemlins/biggrin.gif
The operators manual suggests it needs to be rolling in gear below some max speed. Can't recall what it is right now. That's the way I shift mine and nary a hitch so far. Maybe someone will chip in with the max speed. To shift into 4lo it needs to be rolling verrryyy slowly and in neutral.
A forum community dedicated to all Ford Diesel owners and enthusiasts. Come join the discussion about PowerStrokes, performance, modifications, troubleshooting, towing capacity, maintenance, and more!