2000 Ford Ranger LX, standard cab, 2 WD Rear,
2.5 liter, A4LD automatic transmission, 150,000 miles. My issue is when driving in D my speed ohmeter drops off then my trans goes into neutral. Couple of seconds, speed ohmeter comes back, trans back in gear. If I put the trans in 2nd it stays in 2nd there is no drop off. My trans does not slip or anything. I changed filter, fluid, the 2 shift solenoids...same issue. I purchased a bone yard trans, installed....SAME ISSUE.....there is no speed sensor on the tail stock or anywhere that I can see on an A4LD trans...has to be electical in nature. Need Help.

 

Don't know if this is of any use to you, but my 02 4.0 did require a bit more than the usual amount of distance between the gears and the shifter pointer or it would slip out to neutral.
Try just tapping the shift lever down when it does that.
Other than that one issue, the transmission in that truck is like brand new with over 150,000 miles on it. I've never touched it other than a fluid change.