Have a '99 F350 CC 4WD Powerstroke with auto. The past week or two, I've noticed that after starting truck and then driving, it doesn't always shift all the way down to overdrive - it'll run thru the gears and never get beyond 3rd (drive). If I pull over, shut off the vehicle, then turn it right back on, it'll work, and shift thru all the gears. It doesn't do this everytime, and it will only do it when starting it - not after it's run awhile or anything like that. Weather does not seem to be a factor. Any ideas why it won't shift down into OD sometimes? And why, if I stop and shut it off, then turn it back on, it'll work correctly?

Thanks in advance,

Rick

 

Is it cold where you are? There is software that keeps the transmission from going to overdrive until it has warmed up to a certain temperature.

This software looks at the temperature when you start the truck and adjusts from there. When you shut the truck off and restart, you now have a warmer initial temperature and the cold software won't operate.

A shorter explanation would be that it's normal.

Mark

 

Live in western MT - don't think temp has gotten below 10 yet. I figured there was something in the computer that wouldn't let it shift into OD right away - I've noticed it taking about five minutes of driving time before it will drop down. But in this situation, I have driven over 10 miles without it shifting into OD on days where temp is above 30. Maybe a sensor isn't working right?

 

The shifting you questioning is normal operation when cold. I also have a 99 powerstroke, and have the same situation on cold days. This is built in to protect the trany.



Ross

 

No, it isn't to protect the transmission. It's to warm the engine faster. There is no reason the transmission can't be in overdrive at any temperature.

Mark