Fresh rebuild 4r100 No Overdrive

cjanderson · Nov 13, 2016

Need advice. Just rebuilt 2001 7.3 psd w/4r100 with pto. mechanical diode had failed. Replaced with updated direct clutch drum w/ sprag. New clutches, steels, bearings, and seals. Also installed sonnax sure cure kit.Other than sure cure kit, all stock no programmer.

Transmission will not shift into Overdrive. Put Matco scanner on it, pcm is commanding 4th, but no go. 1-2, 2-3 is good. Reverse is good. Has engine braking coasting down hill in manual 2 & 1.Modulated tcc reads out good. cc and shift solenoids come on and off as they should. No valves sticking. Trans only throws p0783 code for 3-4 shift failure. Can't figure it out, any ideas would be appreciated.

6.7powerstrokeguy · Nov 13, 2016

]their are three bolts that you install the holds the center support and intermediate od cylinder in place. I would check to see if they are loose or missing. I know this may sound like stupid question but their is snap ring the hold od clutchs in the case and is it their?

cjanderson · Nov 13, 2016

ya the fluid transfer bolts were replaced with the rebuild and were tight. snap ring for overdrive piston was replaced with updated spiral ring. and the retaining ring for overdrive backing plate to case was upgraded to thicker to close up od clutch tolerance.

6.7powerstrokeguy · Nov 13, 2016

hmm i looked over the sonnax sure cure kit and I see that you are messing with small section of accumulator body , that hold the 3-4 accumulator valve. I would check to see if the valve maybe hung. them valves are very touchy and sonnax makes a bore sizer for them.

cjanderson · Nov 13, 2016

I pulled the valves and none of the accumulator valves are sticky

6.7powerstrokeguy · Nov 13, 2016

did you replace valvebody plate gaskets?

sideactiondiesel · Nov 13, 2016

Also check 3_4 springs. We see any of the springs being broke all the time . Almost every rebuild we see .

6.7powerstrokeguy · Nov 13, 2016

sideactiondiesel said:
Also check 3_4 springs. We see any of the springs being broke all the time . Almost every rebuild we see .

I built many e40d and 4r100 and never seen a single broke spring. now I have seen the 2 to 3 shift valve hang.

6.7powerstrokeguy · Nov 13, 2016

I know u said u replaced the direct drum sprag but did you also mess with the od sprag?

cjanderson · Nov 13, 2016

it was out during the rebuild and u can't put it in backward, I checked, so it should be fine. I've had this tranny out, torn down, and back in like 4 times and I can't figure it out.

cjanderson · Nov 13, 2016

accumulator springs were never broken and I replaced them with the sure cure kit

cjanderson · Nov 13, 2016

plate gaskets are new also

6.7powerstrokeguy · Nov 16, 2016

I would get a solenoid pack. it maybe a hydraulic leak in the solenoids.

cjanderson · Oct 28, 2017

Update: I believe the problem must of been a sticky valve. It must have only been sticking with fluid pressure on it,because when the valves body were out I could move all of them easily with a pick. I ended up having to drive the truck anyway without OD. Then somehow after around 100 miles it shifted into OD. It stuck a couple times after that for about 50 miles, then quit. Shifts into OD everytime flawlessly. Put about 500 mile on it until I had to stop running it to get body work done for WV state inspection. Thanks everyone for the help.