I have returned after a long hiatus as a man in need.
I have had this Ranger for 5 years, and this is the first real trouble I have run into, and I hope it isn't that "real."
1998 Ranger Extended Bed 2x4, Automatic 2.5 L 4cyl. Her name is Truckenstein.
So I am driving like normal, I have never had any tranny problems, and after about 45 minutes of my typical hour commute, on the highway, the truck starts feeling like she is going in and out of gear around 65mph. Then I start to slow down, and it downshifts with no problems, until BOOM, it goes into first like I got rear-ended. Now just about every time I enter and leave first, it seems to drop it into gear with a vengeance, it does feel like I've been hit each time with a little love tap from the car behind. It all happened very suddenly, and without any known event to cause it.
Oddly enough, shortly thereafter the stupid P0171 code pops up, something I've struggled with in the past because of a stupid aftermarket CAI, which I have removed in pursuit of solving this problem. I replaced my MAF sensor and removed the aftermarket CAI for a stock system, with a plain ol' paper filter (no oiled filters).
This did nothing, so I changed the ATF fluid and filter, also, nothing.
Finally, swapped out the ABS sensor at the rear differential. Nothing.
I have heavily researched similar problems and I cannot find one exactly the same, it seems to shift okay occasionally, like 1 in 4 times, but I can't figure out what is different when it does this. It seems to get worse when it warms up, as each step I would go diagnose it and think it was fixed, until I kept driving for a few minutes. It doesn't seem to shift as hard, but I haven't driven it to the extent I normally would to let it really warm up either ( not longer than a 15 minute drive, although I did get it on the interstate and it had the same problem in high gear, of "slipping" out of gear). I have NO problems if I just drive it in 1 or 2, as there is no shifting going on, the problems are only in and out of first and the strange slipping in the highest gear.
No codes are currently thrown or pending. I have not had a flashing O/D light. These are the two things that everyone else with tranny problems has that I don't have the luxury of having (thus helping to direct my solving of this issue).
I have found this one forum
(I found many actually, thus why I completed the steps I already have, but this step seemed more precarious) that speaks of replacing the O/D Servo, but he says it is on the Drivers side, and it's not, and that it is easy to access, which again, I think that it is not.
Any thoughts on this predicament?
Thanks for your time.