Ghost in the Machine

[bhyde]

Hi everyone

I have a question for you that currently has me stumped.

I just purchased a 2005 Sport Trac 4.0 auto with 4x4. Truck has 171000 miles and looks and drive great. Lady who had it drove about 40 miles each way to work so I expect most are highway miles. So out of the gate I did a tune up of plugs, wires, oil and filters plus a new set of tires. Did find the cruise control not working and removed the switch on the master cylinder and cleaned which solved the problem. Have to say the plugs were a bear to replace I guess because in my old age my hands just don't work like they used to. Noticed the tranny fulid was a little dark and was next on the to do list with filter.

So after a week of driving local I needed to go out of town for work for a week about 100 miles away and took the Sport Trac just to get more aquainted. On the way home at the end of the week I was cruising down the highway with the cruise control on running about 70 mph and hit a bump in the road at the beginning of a bridge crossing which was a pretty good "jolt". The truck seemed to stumble and the cruise kicked off and the toqure converter unlocked plus the RPMs went up to 3000+. I hit the first exit and pulled into an empty lot for a look under the hood. I could hear a metalic rotating sound from under the mid section and immediantly figured I broke something in the tranny. Checked the fluid level and all was good. Limped over to a Ford dealer about four miles away and requested they check it, on the phone they told me they could get right on it and after sitting for two hours with no one looking at it I decided to limp on home.

Popped the battery cables off and thought it reset any codes, now I know it takes about 30 minutes to clear them. On the way home the truck ran fine but the tranny shifted a little stiff from 1st to 2nd and 3rd and the toqure converter will not lock up plus the OD/Off light started flashing on the dash.

later that day (Friday night) I had a local shop pull the codes and it is displaying PO721, PO722 and PO723 and the TSS (Turbine Speed Sensor) is giving bogus reading bouncing around from 0 to 400 or so, mechanic said it should be matching the engine RPM. So Saturday morning I roll up under it looking for a loose wire or connector and attempt to find the TSS. Some have it inside the tranny and some are located around the 2:00 position if looking from the bell housing end. I found two, one just above the main wiring harness and a second a little further back both on the driver side. Did notice the soft heat or noise sheild was loose above the tranny and laying right on top of it. Did hear some have a couple of sensors on top of the tranny but I could not see any. Ford told me later that day my TSS is inside the tranny above the filter. I also went over all fuses both inside and under the hood and all looked good.

Sunday moring I got in it to move it in the drive way and discovered my windsheild wipers are also not working and they did before. I can't help but think the jolt on that bridge caused me to break a connection somewhere and the PCM or computer is freaking out.

Sorry for such a long post but wanted to give as much detail as possible to see if anyone has heard of anything like this before. I have searched the net and found nothing yet. I scheduled to go into AAMCO Monday but now I'm wondering if I should just carry it on into Ford and expect them to tell me I need a new tranny.

Thanks in advance for any insite!

Bobby

 

[bhyde]

Update on the wipers...

When checking the fuses I put it back in the wrong slot!!!

 

[PopRichie77]

If there is only 2 sensors on the drivers side, then you have a late model 5r55E trans. The TSS sensor is on the out side, it is the one near the middle of the trans, the one in the rear is the output shaft speed sensor.
If there is 3 sensors on the driver side you then have a 5r55W or S trans and the TSS sensor is in the same location on the outside.
I don't see how hitting a bump would of broke something in the trans, unless you hit bottom. Check the wire connector on the side of the trans, not sure which switch you messed with on the master cylinder, did you do anything to the one under the dash connected to the brake pedal as it also disconnects the torque converter besides the brake lights, it is a 2 part switch.

 

[JK080]

Assuming you have the 5R55E transmission because you can check your transmission fluid level with a dipstick, all the others that are available in the vehicle you would have to check the fluid level from underneath.

If it has a sensor right above the manual linkage, that sensor is referred as the ISS (Intermediate Shaft Sensor) it reads the shell inside. This sensor is found on the late models. The TSS sensor is located inside mounted on the center support so replacing it would require the removal and disassembly of the tranny. You can check its connection of the sensor to the bottom of the case connector in the pan however. It will follow the rpm of the engine somewhat due the fact the converter will "slip", in lock up it should follow the RPMs of the engine. Also it will read zero in gear at a stop.

The codes you have are all for the OSS output shaft speed sensor, I would concentrate on this sensor and not worry about the TSS. This sensor is located on the back part of the case right in front of where the extension housing in bolted on, see the image. The p0721 code is odd, i don't see it much and it refers to the OSS signal being "noisey" meaning interference of the signal. The p0722 and p0723 are loss of signal codes. Look for poor connections or a bad sensor, you can ohm this sensor across its two prongs, it should read 300-750 ohms. Interference or noise problems have been linked to alternator issues, ignition problems and bad grounds.

Having a scanner the can display data would be useful here, you could watch the signal and move the harness around and watch for a drop in the signal. Loose connections, bad wires are common problems, I find myself doing more and more of these kinds of diagnosis as todays vehicles get more overly complicated...