I can't figure it out. The trans in my 2003 4x2 ranger will go into "safe mode", I guess,usually when I first leave my house. It happened more frequently during the colder weather, but will do it once in awhile still. I usually can fix this by restarting the engine and it won't act up for the rest of the day. The truck has a 2.3L with 24K on it as well as the tranny. I did a motor/ tranny swap into a higher milage truck,123k, from a wrecked, salvage truck. One thing bothers me real bad, it seems to wind too long after you pass another car and when the engine rpm's come down it will upshift. I don't think it should do this. I have changed the fluid and filter to no avail.Also, it seems to go into gear with some hesitation hot or cold. It has remained in 2nd at a stop light 2 times which I'm uncomfortable with. It always seems mushy shifting.I really need some input to correct this,
Thanks to all

 

When you did the swap into the truck did you take the computer?

 

I tried to use the computer from the salvage truck but the coded ignition key would not sync with it. You are referring to the computer in the cowl correct. I had the codes removed once before.The only thing it did however is kick the theft light on in the dash.

 

There are some sensors that may be prt of the problem that only thenewer computer will deal with. I think one is the VSS. I am not quite sure what it does.