5R110W Problems & Questions

[363coupe]

Truck:
2007 Ford F250 CCSB 4x4
6.0L 316,000 miles


Problem History:
I've owned the truck for 5 years. It had 142,000 miles on it when I bought it. The truck has been an absolute dream until August 2018. I had a guy fall asleep at the wheel and rear end me at a pretty high rate of speed. Got the truck back from being fixed and I've had problems after problems but the issue I'm having now is the tranny.

Out of the blue the truck had a bad delay going into Drive or Reverse. Researched online and found that it was probably the line pressure solenoid. Pulled the pan, replaced that solenoid & disassembled/cleaned the remaining 6 solenoids. Changed internal & external filters as well as the TFT sensor. Filled it up with new Mercon SP and everything was back to normal.

Three weeks later it starts making the 2-3 shift really quick and now most of the time it just skips 2nd all together and goes 1-3. about 20 miles later, the tow/haul starts flashing, I pull the codes and get P2701 & PO756 (overdrive solenoid). This has me really confused because I can reset the KAM and it functions perfectly in OD for a day or two and then the tow/haul comes back and wont allow it into OD.

My question is why am I having troubles with 2nd gear but the trans is throwing OD codes?

 

[Jtreece]

sub'd for this.

 

[Mark Kovalsky]

This has me really confused because I can reset the KAM and it functions perfectly in OD for a day or two and then the tow/haul comes back and wont allow it into OD.

After resetting it will operate normally until the problem occurs again, then the codes set and the failure mode protection kicks in. In this case, the failure mode is to not use overdrive, which is used in gears 2, 4, and 6, as pointed out above.

My question is why am I having troubles with 2nd gear but the trans is throwing OD codes?

To answer this you need to know how the trans works. It's really a three speed (the final derivation from the old C6 design) with the two speed overdrive unit in front.

Here is how it shifts:
First gear: Overdrive in 1:1, three speed in 3.09:1 Ratio is 3.09:
Second gear: Overdrive in 0.71:1, three speed in 3.09:1 Ratio is 2.2:1
Third gear: Overdrive in 1:1, three speed in 1.54:1 Ratio is 1.54:1
Fourth gear: Overdrive in 0.71:1, three speed in 1.54:1 Ratio is 1.09:1
Fifth gear: Overdrive in 1:1, three speed in 1:1 Ratio is 1:1
Sixth gear: Overdrive in 0.71:1, three speed in 1:1 Ratio is 0.71:1

Depending on a couple of different factors the trans uses either fourth or fifth gears, it NEVER uses all six gears.

So if the OD solenoid or clutch is working only gears 1, 3, and 5 are available.