Not sure if I'm completely SOL or just in a real bind. Left last week from Sacramento area to Reedsport, OR for the dunes. Passed over some major grades in southern Oregon. Hauled our toy hauler and two quads (8,500lbs) here okay and all around for the week. Vehicle is 04' Expy, 5.4, 4x4.

While heading back from the dunes to the hotel the O/D light started blinking (Temps below 190). Pulled into the hotel tonight and while backing the trailer up there was a clanking noise like the hitch was loose. Disconnected and drove it forward and back a bit. At first there was no noise then occasionally a little clanking, then the tranny would hesitate for a few seconds then jerk into gear.

Fluid looks red to pink, doesn't really have an unusual smell. Had my SCT Livewire hooked up to monitor temps. During the drive up here, coolant was usually 190-210, tranny was usually 170-185 with steep grades running it 195-210.

Ideas? We are supposed to drive home tomorrow morning. Oh, and we have five kids and a dog with us. I'm certain this will be end up being a childhood memory.

 

The only way to have ANY clue is to get the codes read. Maybe your SCT can do that, I don't know.

 

Found them.

P1000- OBDII Monitor testing not complete. (I know this is nothing. Drive cycle stuff)
P0743- Torque Converter Clutch Solenoid Circuit Electrical
P0740- Torque Converter Clutch Circuit Malfunction

 

You have either a bad torque converter clutch solenoid, or a damaged wire to the solenoid. You should be able to drive home like that. If the trans gets hot, try turning off overdrive.

 

The friends we are with left this morning to drive 7 hours home. They are going to drop off their trailer, and drive back tomorrow with their truck and other vehicle to pick up all the kids and tow the trailer home. We were hoping taking the load off the Expy would allow us to get it back under its own power. This town doesn't have a tranny shop and the two closest towns have bad reviews.

I'd much rather have it home to work on myself as much as possible instead of being at the mercy of a shop in the middle of nowhere and hotel costs until its fixed. What are some of the diagnostic procedures to check things out?

 

Electrically check the wiring from the PCM to the trans. Check the trans connector for corrosion. If that doesn't find the problem it has to be the solenoid. It could be the computer, but it's 1000 times more likely to be the solenoid than the computer.

 

I would focus on this clanking noise. While there is an issue with the TC solenoid I don't think a failed circuit would cause the clanking. Any chance a u-joint broke or that something happened to the rear axle?

 

I crawled under and didn't see any issue with the u-joints. I initially thought it might be the rear end spider gears or ring and pinion but when I was outside of it and had someone else moving it, the noise sounded like it was coming from the transmission area.

I was looking into draining the fluid, replacing the filter and solenoid in the hotel parking lot. I checked with the local auto parts here but they cannot get a solenoid in until Monday. The auto parts guy said he wouldn't bother changing the fluid if it has a good color and doesn't smell.

Our friends just got home and will be driving back first thing tomorrow morning to help caravan everything home. Crossing my fingers it will make the grades. We put this rig up for sale a couple months ago but no takers. KBB was only $2700 trade in and $4k ish private party sale. Not gonna be worth paying a big bill on this thing. So a little frustrated this might turn into a new car payment that we have never had with this car.

 

Please forgive me for stating something found in the owners' manual. "When towing a heavy load, turn Overdrive OFF to prevent heat buildup from the torque converter locking/unlocking

".

I made the same mistake yesterday for about a mile when towing a FD RX7 back home on a trailer. Truck had no power, was revving around 1500rpm at 45-50mph and struggled to accelerate anywhere above 50mph. Saw it was in OD, hit the button and she jumped to 2200rpm and was much happier.

For reference, the trailer was roughly 1 ton and the car about 2300lbs (missing engine/trans/interior). Well below the 7400lb rating for my 5.4 4x4 with factory class 3 hitch. Sounds like your truck was overloaded.

 

I have used different numbers for towing capacity, from the Ford site (https://www.fleet.ford.com/resources...s/2004_All.pdf) I have 8650 capacity.

I use a weight distribution hitch also which is required. I measure the trailer frame, tow vehicle wheel openings, and take time to set up the spring bars to get the proper squat. I also use a trailer tongue scale to adjust my load for proper 10-15% tongue weight. When towing I always turn off the OD.

I would agree I'm trying to wring out as much as I can get out of the truck.

Our friends left this morning for the 7 hour round trip to come get the kids with the Tahoe and swap the trailer to their truck. We should be heading out about 3pm. I'll be in the pack with the Expy unloaded except me hoping that will be enough to limp it back home. I'm still really nervous about the grades though.

 

Okay so here's a new development. We left Reedsport and traveled to Canyonville about a 2 hour drive. Starting from a stop it would clunk a little and stopping it stalled out. So into neutral when having to stop then back into gear when leaving got around that. Freeway it did fine and up the grades. Pulled into the hotel and went to back up into another spot. That's when you could feel and hear hard clunking and the truck not wanting to move! What does that tell of the issues. Also got a P0712 and P0713. So now no stopping without being able to pull straight through. Six hours and many grades ahead of us tomorrow.

 

Sounds like a torque converter problem as previously suggested. Reverse pitching a fit implies the rearward clutch is dying.

 

First question is then am I safe to keep going if I can park and pull through instead of having to back up? It's been driving good once started.
Second, I can change a TC myself, I'm guessing the tranny will need internal work for the reverse clutch?
Third, where can I find pinpoint tests for the solenoid?

Thanks for the help so far. Looks like we will be trying to get this just good enough to sell or trade in when we get home.

 

I know it's been a little bit of time but wanted to give a quick update. We were able to limp the Expy all the way home. There was one hill that the tranny started slipping and felt like it wasn't going to make it but no other problems all the way to home.

Had to leave town for work just a couple days later with the whole family so it will sit in the driveway until I can get home and start looking into it. When it rains it pours. Our Excursion has blown head gaskets, Expedition bad tranny, Dodge Dakota headers won't pass smog, CBR has bad rear tire. So right now we have no vehicles and have had to borrow our good friends minivan to drive to San Diego.

 

So I am back in town and ready to give trouble shooting a go. I pulled the codes and got the following;

P0712-transmission fluid temperature sensor "A" low input
Transmission Control Module (TCM) detects excessively low voltage from the fluid temperature sensor.

P0713-transmission fluid temperature sensor "A" high input
Transmission Control Module (TCM) detects excessively high voltage from the fluid temperature sensor.

P0750-Shift Solenoid 1 Circuit Malfunction
The P0750 code is detected when TCM detects an improper voltage drop when it tries to operate the solenoid valve.
When the a transmission solenoid is malfunction, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is very dirty, it is recommend changing the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a transmission mechanical failure and that the transmission will need to be rebuilt or replaced.

P0753-Shift Solenoid 1 Performance
ECM has detected a mechanical fault with the solenoid energized, valve stuck off

P0743-Torque Converter Clutch Circuit
The Torque Converter Clutch (TCC) solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter. Lock-up operation, however, is prohibited when A/T fluid temperature is too low. When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

P0740-Torque Converter Clutch Solenoid Circuit
The torque converter clutch solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter. Lock-up operation, however, is prohibited when A/T fluid temperature is too low. When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

Some of this makes sense. It appears it is electrical related either wiring or malfunction. The low and high errors relate to what I saw while I was driving home. The temp would spike to record highs then also -190 degrees! I also experienced it not shifting into overdrive on one hill as one of the codes stated. Issues locking the torque converter caused me to stall out once which was also a symptom. So a picked up a new solenoid, fluid and filter, and will check the wiring to see how that looks. I have read sometimes the exhaust burns the wiring so we will see.