My transmission will not shift into overdrive. I believe its the A904 what are some things that would cause this.? Any help would be appreciated because i dont like the fuel mileage im getting out of my 318.

 

Getting any codes?

PCM has a few conditions that must be met before it will allow O/D. On yours, there ain't many, but, speed needs to be above about 42mph, engine load needs to be reasonable, and trans temp can't be over some value that I just can't remember at the moment. Of course, that assumes that you even HAVE a trans temp sensor. (usually in the front cooler line, just a couple inches from the trans.) TV cable adjustment plays a role there as well, but, if the trans shifts 1-3 properly, that likely isn't it.

 

No trans codes. I have a code for egr stuff but i wouldnt think that would effect the trans going into od could be wrong though.... I do not have a trans temp sensor.

 

Does TCC work??

 

How do you check that? You mean the torque converter clutch solenoid correct?

 

Yeah, torque converter clutch. If your truck has a tach, just go for a drive, and count the shifts, should be able to feel them in any event. Should go 1-2, 2-3, and then TCC engage. It only drops RPM by 100-200, so, it isn't a big drop. O/D, on the other hand, when it engages, IS a pretty significant drop.