My 98 f150 doesnt like to go into overdrive when its cold. If its cold outside, 40 or below, it wont go into overdrive until 3,4 or 5 miles down the road. When everything is warmed up or the weather is warm it shifts fine. No problem with any other gears or shifting. About 10k miles ago I ran some tranny flush through it and changed the fluid( torque converter and all) hoping it would stop but it didnt.
Its really not an issue because its done it for a while and still shifts fine I was just curious as to why its doing it. It a 98 f150 2 wheel drive 4.6

 

It does that to keep the engine revs higher, so that the engine will warm up faster and get heat into the cab faster. It's working as designed, there's nothing to fix.

 

I never knew that.

It doesnt get cold enough for it to do it here in south georgia too often.