I have a 1995 Ranger 2.3L 2WD automatic with 195k miles.

When I first start the truck, it shifts hard for the first 5-10 miles. After that it shifts normally. At the first shift the O/D light flashes and it throws code P0715. After I have driven the 5-10 miles, the O/D light turns off and the truck drives normally.

I have replaced the speed sensor twice. The speed on the dash is consistent and smooth, which to me demonstrates that the speed sensor is working.

Out of ideas. Any suggestions on what I need to investigate next to avoid taking this to a mechanic.

 

Welcome to FTE.

I'll see if I can get things started.

The code is for an Internal tranny sensor, so it may have problems.

BUT there may be other things to consider. How is the tranny fluid level & condition of the fluid?????
How long since the last full tranny fluid pumpout & filter change????

 

I had some transmission work done about 2 years ago, had the solenoids replaced. The fluid and filter were replaced then. Just check the level about a week ago and it is ok.

It is a second vehicle for me, so it only gets use once or twice a week.

 

OK, good feeback. Had the tranny fluid & filter been changed on time (every 30K miles previously) & was the fluid then ok when the tranny work was done, not oxidized up????
If the tranny has had regular scheduled maintenance over the years, such that you know it's innards are likely clean, no varnish or sludge deposits, then we can likely take deposits, overheating, ect, off the suspect list

This trouble code is for the input turbine speed sensor/circuit low input to the computer.

So the wiring to it, & the speed sensor belong on your suspect list, so check the wiring & connections to the turbine speed sensor before replacing it. It'll be toward the front/engine end of the tranny. Sometimes it's a wiring harness or connector problem, so if the wiring looks ok, pull it's electrical connector & check for bent pin/s, spread socket/s, corrosion, loose or corroded wiring connection to the pins, ect.
Do a location search for a more exact position of the speed sensor on your year/model tranny.

If all that looks ok, give the connections a wiggle test, or the speed sensor a thump with a wooden item & see if things change.

If it's setting where critters can get to it, they like to chew on the wiring insulation, so maybe one has had lunch on the wires going to it, or maybe a wiring harness bracket, ect has come loose & caused mischief !!!????

More thoughts for consideration, let us know how it goes.

 

I have had critter issues in this truck. I checked as much of the wiring as I could see/reach and did not see any damage and all the connectors look good.

As for the 30k fluid changes, that was not done.

When I did drop the pan and change the filter, I do not recall what the fluid looked like.

It is looking like it might be an internal issue and time for a trip to the mechanic.

I really can't complain, 16 years and 195k miles, it deserves a tranny tune up.

 

Has the problem come about slowly over time, or suddenly after some event????

If you suspect sludge, gum or varnish depostis have mucked something up, you might consider a short run of a detergent cleaner upper like SeaFoam Trans Tune, drive it until it stops acting out, or doesn't get any better, then pump the pan out, drop it to clean it & the magnet up & change the tranny filter, refill the pan with the amount removed, loosen the tranny return line at the radiator, or aux cooler & route it into a catch container & continue the pump out one or two qts at a time at idle speed, stop & top it up & continue until the tranny pump has pumped out the full specified tranny capacity.

This will remove virtually all of the old fluid & loosened deposits from the valve body, torque converter, radiator, aux cooler & lines.

If no joy, have a tranny shop look at it, maybe they can spot something obvious with it up on a lift. If your lucky, maybe your model tranny can have the speed sensor replaced without removing the tranny, if thats deemed to likely be the problem.

More thoughts for consideration, let us know what you find.