2003 with Shiftable Automatic, won't shift to 4th - Help!

[BenjiHoggi]

My brother has a 2003 Sedan with 4-speed shiftable automatic and about 185k miles. It won't shift into 4th. Have not confirmed whether it shifts to 4th in manual mode, but I am guessing not, since he basically cannot drive at highway speeds. Also have not heard anything of a CEL.

I have a manual P5 so I don't really know anything about the automatic models or automatics in general.
Is 4th gear just an overdrive? Would no 4th indicate an issue with the torque converter? Is there a possibility it's a sensor or solenoid or something to that effect? Or just a fluid flush? Or a speed sensor?

He is currently several hours from home and limping it back, but concerned that he might be harming other components.
Any ideas? I am also scouring the forums and service manual as I write this.

Much appreciation.
Ben

 

[sleeprp5]

I know there is a procedure to test the shift solenoids on the trans but I cant find it now. I would suggest dropping the pan and testing those solenoids. Good chance one of them had failed. Also good time to do a fluid and filter change and see what the old stuff is hiding.

 

[BenjiHoggi]

I know there is a procedure to test the shift solenoids on the trans but I cant find it now. I would suggest dropping the pan and testing those solenoids. Good chance one of them had failed. Also good time to do a fluid and filter change and see what the old stuff is hiding.

Good suggestions. I will see how much of that I can do when I see him next and can look at the car.

For the moment, it sounds like it finally shifted to 4th and is working fine for the moment. Definitely makes me a bit antsy to see what the problem is though.

 

[pcb]

Keep in mind the stories about people that have changed their ATF and it messed up there transmission.
If the ATF has never been changed it can be best to filter it and reuse it or replace a liter or two at a time to allow the transmission to adjust.

 

[BenjiHoggi]

Noted, I remember reading that several times so I will make sure that it is done properly if it does need flushing. Thanks for the reminder.