So I hope I’m posting this in the correct spot, thought about the 6.0 thread but it had a lot of head gasket threads -_-

I own a 2004 f-350 with the 6.0

vehicle has 68k original miles

I bought this truck used with 48k miles from the second owner knowing it had a trans problem.

Initial seat of the pants troubleshooting was i noticed it had a delayed reverse engagement. Drove it for about two years till one day the trans stalled every time you put it in drive. I figured time to rebuild it.

Got it rebuilt from a trans shop down the street and to my memory it was ok until I put a programmer on it. Had a bad 3-5 flare and towed a trailer home from glamis and let’s just say it **** itself.

Got it rebuilt under warranty from the same shop (this was approximately 2 years ago)

2 days later at a stop light I felt the converter engage and it tried to drive through the brakes and stalled the engine out. Pulled over checked the fluid and it was around 3 quarts low. Filled it up and haven’t had a problem since a couple days ago.

My wife was getting ready to back the truck into the driveway and as I was unloading my service truck is when I heard her shift to reverse from drive and the engine lugged down and shut off. She put it in park fired it up and it went into reverse no problem.

I would like to add that maybe 1500 miles ago I did a trans service on the truck. I replaced the toilet paper roll filter with a motorcraft filter and the trans cooler with a mishimoto unit. Ford Mercon lv oil and has been doing great until a couple days ago.

the toilet paper filter has always been metallic grey when servicing since I owned the vehicle.

so now I dropped the pan and tested the internal wiring harness. No short to ground and continuity is good. I’m going to replace the pca solenoid and the tcc solenoid just waiting for the parts to arrive.

I’ll also check continuity on all the wires to the pcm

any suggestions? I think I’m also going to add a couple grounds from the transmission case to Chassis frame. I hear that’s a big problem for these transmissions.

 

I had a suggestion, but it's too late since you replaced parts that were not the problem.

Stalling in reverse is usually caused by low trans fluid. You should have checked the level before replacing parts. If you did check the level and it was fine, then you need to look into why the line pressure is low. That can be caused by a loose/missing internal filter, worn pump, or leaking internal seals.

 

Hey mark, which parts are you talking about? The pca and tcc? why does it seem so intermittent? If it was losing pressure I would suspect it would happen again putting in reverse.

im 90 percent sure the fluid was correct because I checked it recently and the level was fine.

 

Yes, those are the parts I do not think can cause this problem.

How would either of those parts know to engage the TCC in reverse, but not in any other gear? If the TCC was bad it should stall in any gear when the truck isn't moving.

 

ok that’s good info. Because it’s so intermittent would a pcm/Tcm be a possibility?

What info do I need to know when monitoring transmission pressure?

 

It is very unlikely to be the PCM/TCM.

To monitor line pressure you need a 0-350 PSI gauge with a 1/8" NPT thread. The port is on the driver's side of the trans, towards the front of the trans, just above the pan. Record pressures warmed up at idle in each position: PRND21

 

started out by replacing the solenoids I already ordered pca and tcc.

I separated the valve body and stumbled upon my first possible culprit.

The gasket with the white rubber had two areas that could possibly have caused a pressure bleed off.




Second thing I came across (which i think was the initial cause on stall in reverse) was a slightly opened up pin causing a loose connection on the harness side of the plug in the side of the trans.

pin 1 on the harness side of the transmission plug on the side which controls the sspc-e low/reverse was opened up which I believe was an intermittent loose connection. See pics





I bent it back flat, id really like to replace this harness but this will do for now. i tested all the wires to the from here to the pcm b connection and all tested fine.

Test drove and wow what a difference in shifting the gears and going from park to reverse. I would sometimes get a short delay then a slight hard engagement. Not anymore.

Mark here’s my pressure readings. Trans fluid temp was at 160 degrees F

idle
p/n-55 psi
r- 100 psi
d- 90 psi
3-90 psi
2-90 psi
1-90 psi

oh and I also replaced the cab to frame ground with a 4 awg wire and added 2 more grounds from transmission to chassis frame.

IMO 4awg is overkill but it’s what I had on my service truck.

I’ll test drive it tomorrow again and keep everyone updated.

 

I think you've got it.

 

IMO adding grounds from the transmission to the frame is totally unnecessary. The best approach is to just maintain the factory grounds.

 

I’m not sure how clean the mating surfaces of the engine and transmission are, I didn’t install the transmission IMO the bolts on the bell housing should be enough. If you do your research lots of Failures on the transmissions with arc marks are due to poor ground.

Could be unnecessary but the solenoids are negative triggered, the additional ground won’t hurt anything.

 

Most of the occurrences that people generically talk about are from the starter shorting out and trying to find a path back to the batteries. Not an issue w/ a 6.0L's 5R110W.

I would like to see your research on the 6.0L in this category because mine convinces me that it isn't an issue (and I do not consider powerstrokehelp.com a reliable source). I have also read the "certified transmission" article and disagree with it. I think it is a poorly reached conclusion.

This topic has been discussed a fair amount before. My question never gets answered ..... "Where does this stray current come from?". From what I can tell, the transmission is not intended to be grounded to the block or frame. The low amperage sources of electricity are not going to weld parts together internal to the transmission. Even the potential for "electrolysis" damage is a stretch. The solenoid grounds occur back to the PCM through the harness (PCM actuated).

The best suggestion is to just keep the factory grounds in good shape.

 

I heard this theory from a friend of mine who’s cousin rebuilds transmissions.


I’d like to hear your theory of the cause of the arc marks across the pump and the welded pump.

 

I've seen this happen before, but it is really, really rare.

The original ground strap was missing. Electricity will find a way to make a circuit if it can. On this vehicle the starter ground was through the engine to the trans, down the driveshaft, into the axle, then the springs, and back to the frame. It destroyed the u-joints in a very short time. I forget how many miles, but it was ridiculously short. It also damaged the bearings in the trans (this was a manual trans vehicle.) A new ground strap fixed it.

 

I asked you where the source of this arc would come from and would like to hear your thoughts. Otherwise this will turn out like the other threads - just emotional responses to internet claims. I just don't put confidence in a "rare story" (or a third-hand story) without hearing a technical reason for it. That reason MUST include a source for that current flow to have technical merit.

I already posted that the starter wiring and ground is isolated from the transmission on our trucks. The starter grounds to the block directly thorough the case (no wire or strap to fail except the MAIN ground wire from the bottom of the block to the passenger battery negative terminal). IMO adding a grounding strap from the transmission to the block ADDS to the potential of current going through the transmission (still a slim chance), not reducing it.

As I previously posted - you need voltage and amperage to cause damage and it is HIGHLY unlikely to have that in our truck's transmissions. Granted, anything can happen! Someone can weld on the frame or possibly contact the transmission case with a high amp 12V source (like a battery cable on an E-series), but that is such a low probability. Really .......... next we will be adding another ground strap to the PCM, FICM, etc.

Again - simply put - the voltage and amperage that can reasonably get to the transmission, is not enough to cause the damage. The positive wires to the solenoids are small gauge. Same with the power supply to the range sensor, the temperature sensor, and speed sensors. Check out the wiring diagram for the transmission and the wiring is not going to convey high amps (C1107, C1385, C1387).

In the very early 6.0L days, some plastic pressure sensors were installed, but not used. Soon after the early production, the sensors were not even installed. No issues with them as they were manufactured but now shops are trying to sell unnecessary plugs.

Not everything you hear from shops is true.

Mark K. would be the most qualified person on our forums to "hypothesize" how this could happen on our 5R110W transmissions, because other than what I posted I can't see it happening.

 

Also as I posted - the best thing to do is to PROPERLY maintain the factory grounds.