I have an 06 F-250 with the 5.4 V8 and 5R110W Torqshift transmission. I am having very intermittent problems with the transmission. For example, yesterday I drove 200 miles towing a car and the transmission shifted flawless the entire time up and down decent sized grades. On this trip, I stopped for gas and when I continued on the freeway I got a hard down-shift from 5-3 or 3-2 (not quite sure which) After the hard downshift I continued driving and there was some erratic shifting like searching for the right gear and not long after I got a pretty hard jolt or bang. I pulled over to the side of the highway, put in park then tried to drive again and the engine was revving up but the truck was barely moving and then a hard slam almost like it was thrown into park

I called a tow truck and got the truck towed to the Ford dealership. Today I went for a test drive with a Ford mechanic and the truck ran perfectly. We drove all over town without a single problem. Went back to the Ford dealership and we scanned the truck and there were NO codes. I dropped the mechanic back off at the dealership and continued driving the truck for about an hour and it was flawless.

Parked the truck and ate lunch, when I got back in the truck and drove it I came to a red light and stopped. When the light turned green the truck was revving up and barely moving again. I pulled to the side of the road let off the gas and back on a couple times and it was fine again and continued to drive perfectly

Parked the truck again to work for a couple hours then decided to drive the truck again and drove it for 50 miles. Flawless shifts.

Parked the truck again for an hour and then drove again and after a couple miles it acted up again. Revving up but barely moving, then slamming then I would slow down and then speed up again and everything was perfectly fine again and drove it for 20 more flawless miles.

The problem is almost impossible to replicate for a mechanic and I'm at a loss for what to do. I would hate to replace the transmission if it is some sort of electrical problem, sensor problem, etc that might stay with the truck even with a new transmission.

I have already dropped and cleaned the pan, replaced all of the fluid using Frank's full fluid flush method (link to video at end of thread) and replaced the external filter but this didn't help the problem. This is a new to me truck that Im pretty sure was traded in because of this transmission problem. I did find a quart of Mercon V in the engine compartment which is why I did the fluid exchange to get all the Mercon V out.

Any ideas would be MUCH appreciated

 

When we see transmissions that seem to only have issues when they are hot or after driving long distances the problem is usually caused by a interneral leak in the valve train of the valve body or seals/gaskets that seals off hydraulic passages. The fluid gets thin when it's hot and pressure drops due to the leak it can cause all kinds of shifting problems or failures of clutches or converters.

Yours seems to be having issues only once its hot and it's more of a shifting control problem rather than a converter issue, so I would think the problem would be more related to the solenoids or the valve body. The 5R110W doesn't really have a valve body like most other transmission but they do have problems with leaks like any other valve body. The manual valve wears on these and so does the pressure regulator valve in the pump but this usually causes delayed engagements and or low line pressure so that doesn't fit your description of what happens. I have seen problems with faulty solenoids and leaking end plugs cause shifting issues so that's what I would suspect. I have used Sonnax for replacement valve bodys for these when we have water contamination and have had good results, they come with solenoids and oversized manual valves and sealed end plugs all of which are known for problems anyways, so it's a good bang for your buck if you wanted to take a educated guess.

 

I've seen bad PCMs cause this. Its shifting into 2 gears at the same time which is very bad for the trans and will break hard parts in short order.

 

Thanks the input guys. I will probably make a new thread but wanted to follow up here too. I found an almost brand new valve body from a local guy who bought it brand new and put it in his truck whose transmission was having problems. Turned out not to fix his problem and it was only installed for a few days. Anyways, I bought the valve body and threw it and all 7 solenoids into my truck.

Now I am getting an occasional code P0761 and every now and then upon low to moderate acceleration the truck will shift from 1 to what feels like neutral or 2 to neutral. I let off the gas and it will go back into gear and everything is fine again. I have a scangauge so I clear the code when it comes on and the rest of any trip is usually perfect with no tranmsission problems

Havent had the original problem return yet so hopefully if I track this new problem down I'll be OK

My next step will be to replace the wiring harness as I did bend the pins a little bit upon unplugging of the harness above the valve body (the bolt holding the 2 connector pieces together broke upon loosening and the remaining piece had to be vice clamped onto but it would not un-thread and ended up bending some pins as it twisted and broke some surrounding plastic)