6r80 Troubles...

[redfiresixer]

This is my first post here in a long while, but I cannot find the information or help I need anywhere so I figured I would try here too. As background I have a 2012 5.0 with the 6r80, mods include Paxton kit, 4c converter, exhaust, etc.

My problem is that while driving, after the car has warmed up, it will not shift into 4th. It doesnt hang in 3rd, it actually feels like it downshifts to 1st. 5-6k rpm at 30mph. I can drive the car fine in 1-2-3 manual selection but in drive it will not go to 4th gear once its warm. Cold operation is like stock.

My first round of diagnosing included replacing a blown #49 fuse (rear o2 sensors deleted and the wires had melted to exhaust,) and fixing melted wires for the right rear abs sensor. Those two issues have been resolved, abs works great and all wheel speed sensors read the same speeds, fuse has not popped since fixing the o2 wire either.

I have also tried:
- return to stock, reflash with tune (used 2 seperate tuner's files)
- remove valve body, clean, new fluid and filter, new shift solenoid e
- test molded lead harness on valve body
- test individual solenoids
- test wiring from transmission to pcm

No codes have been thrown except for Shift Solenoid E and Shift Solenoid E electrical but I cannot get these to repeat after clearing.

My most recent attempt to diagnose I datalogged the car hoping for some new info. When the event occurs every solenoid is at maximum pressure and the transmission line pressure is over 315psi. I don't know about what the line pressure should be at but I know every solenoid should not be active at once.

Does this point to a Pcm issue? I cannot find a way to test the pcm for internal shorts. A new Pcm will run $270 plus a $35 reflash and the hassle of having to retune the car. Just want to confirm this before throwing parts at it.

Thanks for the help!

 

[weather man]

Gut feeling only, based on info provided, sounds like internal hardware issue.

 

[redfiresixer]

Internal as far as the transmission? Are we talking about the clutch packs and drums or the valve body? I have inspected the valve body and could not find anything wrong with it. Cleaned it and reassembled. All solenoids and the molded lead harness check out as well.

Im stumped as to why every single solenoid in the transmission would be active at once. I cannot find any case like this anywhere.

 

[weather man]

Internal as far as the transmission? Are we talking about the clutch packs and drums or the valve body? I have inspected the valve body and could not find anything wrong with it. Cleaned it and reassembled. All solenoids and the molded lead harness check out as well.

Im stumped as to why every single solenoid in the transmission would be active at once. I cannot find any case like this anywhere.

My thought was something frozen/stuck and pressure spikes trying to make it work.

 

[redfiresixer]

Do you think the overdrive drum could be getting stuck? This also only occurs once the vehicle is warm. It operates fine in all gears while cold.

 

[weather man]

Do you think the overdrive drum could be getting stuck? This also only occurs once the vehicle is warm. It operates fine in all gears while cold.

The pickup guys complain about the overdrive snap ring and clutch doing something similar to what is happening to you.

I definitely think hardware.

 

[redfiresixer]

I cant find any info about the 6r80 trans in the f150 doing the same thing. Any way you could provide a link to a similar problem?

 

[weather man]

Can't find the damn link again, sorry.

 

[redfiresixer]

Any other input? Id like to have something to go on a little more concrete before tearing into the transmission.

 

[Pentalab]

Is the ATF level correct ?

 

[redfiresixer]

Yes, transmission fluid is at the full line at 165 degrees. New fluid and filter.

 

[redfiresixer]

Had a friend of mine suggest testing the Turbine Speed Sensor and the Output Shaft Speed Sensor for shorts or opens and correct operation. Will probably do that tomorrow morning when I get off work.

Will keep this updated with results.

 

[KrisR]

Is the wrench light coming on?

Mine had to go in for a TSB (13-6-8) because of erratic speedo/shifting issues and the fix was to replace the 'Molded Leadframe' in the 6R80 trans. It was a free fix covered by Ford. Might not be what you're experiencing, but I thought I'd throw it out there...

 

[redfiresixer]

No wrench light or check engine light. No codes.

My datalog tonight shows that the pcm is commanding incorrect solenoids for each gear ratio. This keeps pointing to a pcm issue. I am going to order a new pcm tomorrow and hopefully my tuner can get me a start up file quickly. Crossing my fingers that this is it. Im about ready to return it to stock and sell it at this rate.