Yeah 2000 Accord V-6 with 157,000 miles here. Mine has a delay shifting into D4 when the engine is cold. Only happens in the morning or if the car has sat for 8+ hrs, otherwise no problem getting into gear when engine is warm. I have to wait till the engine temp gets to or past the lowest hash mark on the gauge, or rev the engine past 2000 rpm a couple of times. No flashing D4 light, and the tranny shifts flawless otherwise. Fortunately I have no problem with reverse.
I have done the 3-refill flush and installed a Magnefine filter, hasn't resolved the problem but at least I know this will save the clutches.
I am in the process of rebuilding a spare BX7A tranny and I think I know what the problem is in my case (not the OP's). There is a servo piston that controls the gear selector shaft, and the O-ring around it is probably worn and flattened out. When the tranny fluid is warm, the rubber expands so it holds pressure. Requires pretty much a 75% teardown to replace.
The OP might want to remove two of the solenoids that have accessible screens to see if they are plugged. The solenoids are a bit of a ***** to get to with the tranny in the car, though. But cleaning the screens only solves half the problem: that means the clutches and bands may be worn, so the tranny can crap out at any time if it's slipping.
I give it a shot.
