OK, started about 4 months and 7000 miles ago. First symptom was 2 to 3 second (longer than normal)delay from park to drive. Took it to Ford they said was within specs, keep driving. Towed my 5er to south florida and back, problem was pretty much the same. 2 to 3 second delay park to drive, everything else was normal. Towed about 1000 miles last month and the delay was up to 3 to 5 seconds. I started doing research and was convinced that the Line Pressure solenoid needed to be replaced and I was going to do it myself.

However, just this evening the delay went from seconds to "Holy crap, this thing ain't gonna go". The truck would not move in any forward gear, it would move in reverse. I was finally able to get the truck into my shop and parked. Question, is the line pressure solenoid still a likely trouble source or do I have bigger problems? All help is appreciated, knowledgable help is really appreciated. Thanks.

On Edit: OK. truck sat over night, it's a little cool at 65 degrees (well, this is Georgia). I went out and started the truck. It now goes into drive with a 5 second delay. So, add that to the clues. I'm gonna let it sit over the weekend and decide by Monday what to do.

One more update. I drove the truck today and changed some of the tunes. Nothing changed so I went back to a tune of stock. I was able to repeat the situation where the truck has no forward gears, twice. When cold the truck drove nicely with a delay from park or reverse to drive. As the tranny got warmer the delay seemed to get longer, up to maybe 5 or 6 seconds. Once warmed up 150 degrees or so, oif left in park for a while (15-20 minutes) the truck will have no forward gears. I was able to wait and let it cool a bit and then it would shift hard into drive. Once it shifted in to drive the truck runs and shifts fine. So, I guess it's something more than a solenoid. Now the question is who do I want to work on it? Any suggestions?

 

I have replaced the line pressure solenoid on a few of these including my own, its about the only thing you can do to correct the delay short of pulling it out and going through it.

If you install a line pressure gauge you can watch the pressure and see if the solenoid is not working correctly before you go in.

The solenoids are known to to fail all by themselves but it might be a sign of bigger things to come. The last Torque-shift that I built I installed a new line pressure control solenoid and a TCC solenoid first, it lasted about two weeks until it came back on the hook with the converter locked on and it would kill the engine. Turns out the converter was failing and creating bits of metal debris and this debris was what was causing the solenoid the stick. So I ended up building the whole thing and obviously replacing the converter too.

Once you have the pan off this should be a good indication if there is excessive debris in the bottom of the pan and you may have to make a decision on what to do at that point.

 

Solenoids usually fail from tiny bits of debris. The TorqShift is VERY sensitive to the right fluid, and it must be clean fluid. Old, worn fluid is not clean enough and will cause solenoids to stick. So will an impending failure that is adding debris to the fluid.

 

OK guys, thanks for the responses. I think I get it. The solenoid may be causing the slow shift but something else may be causing the solenoid to fail.

When this first began I took the truck to a Ford dealer. They said it wasn't a problem, it was within specs. Well, it didn't do that for the first 57,000 miles. Anyway I had them change the filter (internal only on my truck) and do a hot flush. According to the paper work I got they used the correct fluid and I would think that since I took it there for a tranny problem they would have reacted had the tranny or the old filter been full of debris. (although maybe they are not that smart, or the person doing the filter change is the 5 buck an hour helper)

So, here's my question, have y'all ever changed the line pressure solenoid (part number 4C3Z-7G383-AA) and had it correct the problem for good?

I'm thinking that by the time I buy and install a 500PSI pressure gauge I might just as well buy and install the solenoid, right? Besides, after I couldn't get any forward gears last night I'm reluctant to drive it any further than I can walk back from. However, if there is little or no chance that the solenoid will solve the problem I might as well find a tranny shop. What do y'all think?

OOps, I put the latest update on the OP. My bad. Today I was able to duplicate the no forward gear situation, twice. When cold the truck would shift to drive with a slight delay. As it got warmer the delay would get longer. Once it reached 150 degrees or so the delay was 7 or 8 seconds. Plus, once at that temperature i parked it for 15 or 20 minutes and when I returned it had no forward gears. Still had reverse. after sitting and cooling for a while it would work again with a delay in to drive. Any suggestions? i think I'm gonna go ahead and drain and remove the pan in the morning and see if I can find any sign of contamination.

 

OK, I dropped the pan this morning and though the fluid was a bit dark everything looked pretty good to me. There was a bit of gray substance on the magnet which I have to assume is metal scrapings. What I don't know is if the acculmation is from 64,000 miles or from 7000 miles when Ford allegedly serviced the tranny. The filter was very clean both the paper and the screen.

Anyway, I ordered the parts and will install a new Line pressure solenoid and see what happens. I'm fully aware that doing so may not be a long term solution but it's worth a try.

As best I can tell from reading on line the solenid I need to change is the one nearest the dip stick. And it is blocked in by a black gizmo that looks like some kind of wire distrubtion center.

Would anybody like to tell me how to remove the black gizmo. I know I have to drop the valve body (I'm told on this unit it's called the solenoid body) but I'm still not seeing how to get that thing out of the way. If I had to guess I would say use a screwdriver to lift the small tab and then turn the unit counter clockwise. But I sure would like to hear from someone who knows.

 

Yea the line pressure solenoid is the one that is blocked by the bulkhead connector on the manifold body. You will have the drop the manifold or solenoid body to get the connector off to get the solenoid out, there is a o ring on the other side of the connector that will prevent the connector from being removed from the bottom. Make sure you disconnect the harness from the outside first.

When your new solenoid arrives make sure there is a "AA" stamp on the solenoid body, all these solenoids look the same but they are different. Only the line pressure control will have the "AA" all the other have "BA" or "CA" stamps. This way you can make sure they gave you the correct one and you don't end up with more issues.

I have just replaced this solenoid on a couple of these and didn't hear back from the customer of any other complaints.

 

JK 80, thank you very much. Now I know. But I won't get to use the knowledge this time. As I looked closely at the filter I started to see a lot of silver/gray fine fine hairs in it. they were in there so well I thought at first they might be part of the filter fabric. Then i went and looked at a new filter and ruled that out. So, I took a magnet and it was clear that the fibers were metalic. I think something is coming apart in there and plugging that solenoid. So, today I took it to a tranny guy who has a reputation for building 5R110 trannys for heavy towing which is what I do. Just waiting to hear what he finds. But thanks again for the info. I may not use it but I bet someone else will do a search and it will help them. One real value of FTE is that shade tree guys like me can learn from more knowlegable guys. Thanks again.