Won't Shift into 5th

[jbair]

History: 2008 Job 3 6.4L tuned at 30,000 miles w/ H&S Tuning, has 6" lift and 37" tires. Tranny was great until I installed track bars at 50k miles and since then I have had a minor slip between 4th and 5th gear and it will occasionally shudder when it downshifts.

Present: Today at 66k miles when I accelerated it did the downshift shutter, threw codes and would not shift into 5th or keep the TC locked in 4th. I pulled over and erased the codes (which was stupid) but I believe they were a drive solenoid stuck code, and a slip code. Once I cleared them the truck would still not shift into 5th or keep the TC locked in 4th. I re loaded my tune and still no luck, I'm trying to make this Transmission last another year as I only drive the truck about 10k miles a year.

Any help is appreciated.

Thanks,

[Rubenk]

Mine did a similiar thing over the weekend.

Cleared codes and still no 5th. I returned to stock(didnt try to start truck), then reloaded my tune, took it for a spin and I have 5th back now.

[drewactual]

most often it is a flow issue that doesn't allow 5th.. it could be an obstruction somewhere like a line or filter, or the flow could be fine but what registers the pressure (sensor) could be jacked..

those solenoids clog up with clutch material, and sometimes 'clear' themselves.. it usually comes back fairly quickly, though, unless whatever is clogging it is cleared out..

change your trans filter, dude, and have her flushed.. if it persists, swap out solenoids.. ask yourself why, though, there is so much clutch material present- and you'll likely come to those tires working the crap out of the trans.. it is just part of playing the game, man.. when you get it all worked out, use the program that shifts into o/d and t/c lock up at the latest point, and you'll save some wear on the transmission in the future..

[Big Angry Hillbilly]

Will only be a matter of time before that ***** needs an overhaul, start saving your pennies. She's wounded, and bleeding.