2005 4.2 F150. The truck has about 270k and the trans has about 40k on a rebuild from a quality local builder, previous owner had it rebuilt. Truck ran fine up until the day it lost overdrive/4th gear. I went out for lunch and on the way back it slipped and then slammed into 4th gear going back to work a few times. When I got back I checked the fluid level and condition, full, red and nothing smelt alarming.



On the way home for about 15 minutes it was fine, got on the interstate for another 15 minutes fine and then it started to slip and fall out of 4th gear, to the point where it wasn’t safe so I slowed down and let it downshift and drove a little bit with the OD off until I called my brother to come give me a tow.



I dropped the pan and valve body thinking the OD servo snap ring came apart and jammed the valve, nothing crazy in the pan other than a tiny bit of normal sludge on the magnet. I pulled the valve body and the dang snap ring was still in place. I went ahead and tore apart the valve body to inspect anyway and it looks like the check ***** were never replaced nor was the valve body serviced with new parts.



I was thinking the trans needed a rebuild at that point but I got curious and started going through the valve body and seeing how well each valve worked. I got to the “Overdrive Servo Regulator” valve and pushed in it with a screw driver and the thing stuck open, I messed with it a few more times and it definitely doesn’t feel smooth like everything else.



My question is would it be possible that the Overdrive Servo Regulator valve sticking could be the problem? Would it be worth buying the Sonnax kit and throwing it in to see if I get 4th back? Or is it a lost cause?



Thank you

 

Not a trans mechanic, but I would guess its the OD servo..don't know if you can get the whole valve body, or if a good transmission shop could rebuild yours. I'll have to look up the Sonnax kit,