Hey y'all, I have a 2003 f-150 with the 5.4 liter and auto tranny and lately since it has gotten colder here in MN- about 20 degrees- i have noticed that my tranny will not shift into over drive untill a while after i have been driving. Is this normal? I did not notice this last winter- but didnt drive it alot then either i guess. Does this have something to do with the tranny fluid warming up? I always idle it for a while to warm the engine- but i guess this does nothing for tranny fluid right? After i have been driving for a while it shifts into overdrive no problem- just like in summer. Kinda sucks for the gas mileage but i am just a wonderin if this is normal. thanks for any responses.

 

The transmission will not shift into overdrive until the engine has gone into closed loop. If it seems to be taking longer to get into closed loop try replacing the front 02 sensors so that it will read faster. Those sensors are heated so that the engine will warm faster. As they age they don't heat as fast.
Alan

 

Well i bought this truck brand new and only have 6500 miles on it- so nothing is "aged" yet. But if something is faulty i still have 11/2 yrs. of warranty. So how long should it normally take to get to "closed loop"- and what is that exactly? I am not familliar with all the mechanical terms. And if there is something wrong with a sensor- shouldn't one of the idiot lights be goin off???

 

Closed loop is the condition where the oxygen sensors are completely warmed up and the engine has complete control of the air fuel raio from them. When the oxygen sensors are cold they do not operate. It can take anywhere from 2-10 minutes to reach closed loop depending on temperature and your vehicle.
Alan

 

thanks dirtyd0g for the info

 

I think that this is normal. I know on my f150 during cold days, it will take about 5-10 minutes to shift into overdrive. This only happens in the winter when the engine is cold. In the summer, it goes into overdrive right away. I am not sure, but I have read somewhere that there is a temp sensor somewhere that tells the transmision when it is warm, and it wont shift into overdrive until then. I am not an expert, but we also have a dodge that does the same thing until the engine warms up, I think its normal.