97 Ford Ranger automatic transmission

ford
ranger
transmissions

#1

Replaced the original transmission about a year ago at 155K miles. Recently has started failing to shift into overdrive at highway speeds, or shifts down to 3rd from OD.

No “check engine”, fluid OK, and mechanic found no fault codes and (of course) could not reproduce behavior. Any troubleshooting tips?


#2

Have you ever replaced the transmission fluid? Did the mechanic do a sniff test to see what condition it might be in? It is possible to do a lot with a transmission without having a CEL. We did have automatic transmission back when I was learning to drive and that was in the days before computers.


#3

Fluid has not been replaced since new tran installed last year. Don’t know about “sniff test”, but mechanic didn’t think fluid was the problem. Level was good. Are we smelling for burnt fluid or what?


#4

The one item I would measure the operation of and/or replace is the Throttle Position Sensor. The PCM uses that as a major input for shifting decisions.

Does the engine seem to have the same power it used to have? Which engine do you have in this Ranger? If the engine is down on power, you would be further into the throttle to maintain speed which might delay the engagement of OD and cause a 4-3 downshift to occur more often. Also check for things that would consume power i.e. low inflation on tires, dragging brakes, seizing accessory, etc.