Apologies in advance for the length - I want to include details of what I have tried to date. Hoping you guys can give me some direction on what my next step should be to diagnose this E4OD. 1993 F250 7.3 IDI. 173k miles 4x2.

A few weeks ago I started getting hard shifts from 1-2. I did some reading and found that the od OFF light could be blinking, but mine hasn't worked since I have had this truck. So I ran to the jy and picked one up for $5. Sure enough, it was blinking.

Then I bought a code reader and pulled codes. I got quite a few of them:
29: vss
43
59
62: excessive tc slip
49

I read here and elsewhere to check the solenoid pack plug/wiring. So I dropped the pan and pulled the solenoid pack. I found that the plug was very dirty and cleaned it really well but the wiring harness all looked good. No exposed wires. I cleaned them with electric parts cleaner and put in some dielectric grease before re-assembly.

I tested the solenoids with a multimeter and the four measured 19.0 to 19.7 ohms, with the EPC measuring 4.5 ohms. So I'm thinking this is all good, and possibly my problem was the dirty connector.

The transmission fluid I pulled out all looks very good. quite red and no burnt smell. I re-assembled with new filter, gasket and re-filled with Castrol Dex/Merc.

Out for a test drive and the first mile was brilliant. Super smooth shifting 1-2... then the damn OFF light started blinking at me again, and the hard shifts resumed. I ran the code tester again and only got 3 codes: 11, 29 and 62.

Now that I have done all that dis-assembly and cleaned up underneath, I saw after the short drive some fluid leaking out of the bellhousing cover drain thing... I failed to notice this before as it is pretty dirty under there.

Thoughts on what my next steps should be? Thanks in advance!

 

A couple more questions occured to me...

Could the 62 be a symptom of the 29 vss?
Could the leak be unrelated to the codes? Doing some more research and it may be the front seal leaking...

 

Yes it is.
Yes it is.
That's about the only place the fluid could be coming from.

All that cleaning you did was a good thing, but had nothing to do with your problem, which is the code 29. That's the vehicle speed sensor, which is on the rear axle, not inside the transmission.

Remove the sensor from the top, front of the diff. It may have metal particles stuck to it (it's a magnet) and that will throw off the signal. It might also be a bad sensor, or a wire from the sensor could be damaged anywhere along it's length.

 

Hi Mark, thanks for your quick reply! Is there any way to test the vss? I pulled it out just when I was putting things back together and it looked clean. I didn't give this much more thought earlier because my speedo has always been fine...

Should I get this part from Ford? Do you know a part number off hand?

 

Another one... how long can I go with a bad front seal? assuming the vss fixes the limp mode? and just checking and keeping fluid levels up? I'll have to organize some parts and down time to try and fix the seal.

Cheers

 

the sensor provides a signal that is very small and corrosion can causes degraded signals or could be the connection at the trans computer, or the ground to said computer how is your speedo behaving, steady or fluctuating? check that the tps is within spec, approx 1.1-1.3 volts at hot idle, use volt meter push the red test probe into the conector on tps, the black probe on a good ground, their is three wires, one will show 0 volts, one should show 5 volts +- .5 volts, one should show 1.1-1.3 and smoothly climb in voltage to the 5 volt point, as you increase the throttle, the sensor is adjusted buy loosening the screws that hold it to the bracket, 2 screws they are torks and tend to strip out, I had to remove the whole bracket to change mine. I replaced the screws with Allen head. you can test it buy turning on key to run.. engine off don't worry about glows they turn them selves of after 120 seconds. the computer has built in error correction and can tolerate some sensor irregularity's. Mark is the trans Jesus on here, I only know enough to get my self in trouble. when the system is operating it compares rate of acceleration, and throttle position, and engine rpm and rate of increase or decrease of all, to determine shift stiffness buy varying internal trans pressure, the early e40ds used a different pressure regulating valve and suffered from mushy shifts, most good shops perform some (fixes) to remedy the problem but because it was busted when you took it to them, they drill the orifices , blind knot knowing you enjoy driving and drinking coffee on the way to work .

 

I think I have this mostly fixed for now. Since it's Sunday I just got a BWD sensor from Advance Auto and plugged it in. Unhooked the negative leads for a few minutes and re-plugged them in. Test drive went great, no blinking OFF light! Shifts very smooth now!

I forgot to mention in my first post that I tested the TPS and it was bang on the spec voltages. Lesson learned, should have replaced the VSS first...

So now I just have to deal with the ABS light, leaking front seal and fuel tank showerheads that have fallen off... I'll just keep any eye on transmission fluid levels since I know the front seal is leaking. Could I be doing further damage by driving it until I can get the seal replaced?

 

If you don't run out of fluid the leaking seal won't hurt anything.

 

Awesome Mark, thanks for the info.

Ugh. I think I jinxed myself and spoke too soon. replaced the vss (BWD brand from Advance Auto) and took it for a ~3 mile drive - all went great. But a couple hours later I went for a drive and the OFF light started blinking again... codes gave me 11-10-29-62-29-62.

Is this suggesting that my new sensor is no good? or that there is another wiring problem between the vss and somewhere else?

 

It could be either, but usually it's the wiring. It could also be the PSOM module on the back of the instrument cluster.

 

Do you know where you coyld get one? I havebt found any place that replaces them and last time i checked the dealership stopped selling them as well. Is there a third party seller out there?

 

I don't know where to get a PSOM.

 

may i ask are u talking about the negative leads as in the battery negative?