Shifting issue
Thread Starter
|
Member
Joined: Jan 2009
Posts: 14
Likes: 0
From: Vancouver
I think I will continue to drive easily, waiting for some local warming, and see if things change. My only issue was that the truck had no issues last year. But last year, I didn't park it for this long. Could very well be a change in the trans fluid, who knows.
If things get worse, I will pull the pan. Again, thanks for everyone's imput. If I find anything, I will post it so everyone learns a little more.
If things get worse, I will pull the pan. Again, thanks for everyone's imput. If I find anything, I will post it so everyone learns a little more.
Member
Joined: Jan 2009
Posts: 33
Likes: 0
It's because it's very cold outside... wait until it warms up, I guarantee it will not happen. Most automatic transmissions with computer controls will do this soft of behavior. It's to protect the unit when the fluid is not yet fully warm. There is nothing wrong with it, it won't blow up, or drop out from under the truck.
https://www.f150online.com/forums/tr...when-cold.html
https://www.f150online.com/forums/tr...when-cold.html
he says he has to let off the throttle for it to shift 2nd...thats a sure sign of a mechanical problem....especially in the 4r100
Senior Member
Joined: Sep 2006
Posts: 292
Likes: 0
From: North Pole, Alaska
The transmission shifts when you let off the throttle because the PCM varies the line pressure according to the throttle position. When the throttle is wide open the PCM increases line pressure forcing the transmission to downshift, when the throttle is closed the PCM lowers line pressure allowing the transmission to shift up. If the TPS tests out good then the problem is internal and the transmission most likely will get a rebuild.
Senior Member
Joined: Jan 2008
Posts: 473
Likes: 0
From: Kansas City,MO
Missed that, my apologizes.
Thread Starter
|
Member
Joined: Jan 2009
Posts: 14
Likes: 0
From: Vancouver
Driving characteristics
As I continue to drive my truck, the shifting issues are getting better. Everything seems normal once it is warmed up, but the shifts are still a little late when driving easily, but OK. The 1-2 shift can come in at 2400. or 3200, depending on whether I am holding an even speed or gently accelerating. The 2-3 shift seems to like about 39MPH when I am not accelerating.
Nothing else seems to be wrong, idle is good, drivability is also good. I guess I'll just have to enjoy the sound of the extra RPM around the neighborhood. At least the price of gas is down.
Question: Should I be worried about the TPS? I have been hoping for a dry day to check the voltage, but it has been wet and snowy. Has anyone experienced the joy of driving to work in their Lightning on a sheet of ice? Nice!!!! But do-able. I drive a 105,000lb tanker for a living, so I like to have fun all day.
Nothing else seems to be wrong, idle is good, drivability is also good. I guess I'll just have to enjoy the sound of the extra RPM around the neighborhood. At least the price of gas is down.
Question: Should I be worried about the TPS? I have been hoping for a dry day to check the voltage, but it has been wet and snowy. Has anyone experienced the joy of driving to work in their Lightning on a sheet of ice? Nice!!!! But do-able. I drive a 105,000lb tanker for a living, so I like to have fun all day.
Thread Starter
|
Member
Joined: Jan 2009
Posts: 14
Likes: 0
From: Vancouver
Problem solved!!!!
After studying the problem and listening to some of the more knowledgeable members, I bought and installed a new throttle position sensor, even though the truck was running fine, with the exception of the shifting issues.
Guess what? The TPS was the cause of the problem, even though the truck never had an error code. It just wasn't sending a signal to the transmission to tell it what the engine was doing.
I hope this helps others.
Guess what? The TPS was the cause of the problem, even though the truck never had an error code. It just wasn't sending a signal to the transmission to tell it what the engine was doing.
I hope this helps others.