Hey guys and gals, I have a Class C motor home with a Ford E350 front. It is a 1992 with a 460 EFI engine and I believe it has the E40D tranny. My problems started on my last trip. When I stopped for gas and restarted the motohome the odometer was not displaying. Shortly after I noticed the speedo not working as well. Then I tried the cruise control and that to did not work. On top of all this the tranny started to get hot. The tranny will usually stay between 170 and 190 depending on hills. Now it is running at 220 to 240. I have done research and everyone says speed sensor. I replaced the speed sensor and still having the same problem. When I unplugged the speed sensor the ABS light comes on. Does that mean the sensor is reading? So what else could it be? I also noticed that the part numbers are a bit different for the sensor. F37F-9E731-AA is the one I pulled out of the rear diff. F85Z-9E731-AB is the new one that I put in and still not work. Any thoughts??
Most likely the PSOM (programmable odometer/speedometer module) went bad. It's integral to the speedometer and receives the signal from the speed sensor. They can be rebuilt, or you can buy a used cluster from a junk yard and swap it. PSOM also stores vehicle mileage so if you end up with a used one, whatever miles the donor rig had will now show on your rig.
Bad speed readings could confuse the engine/tranny computer so it could cause overheating if it is making the tranny run in too low a gear or unlock the TC CLutch or slip gears etc.
One check I would do since it costs nothing to check and probably nothing to fix, I like cheap...
Check your plastic vacuum lines around the engine, especially those around the Airconditioning box on the passenger side firewall. I think they are Red White and Black vinyl looking lines about 1/8 inch OD. Several of them are joined together in black rubber plugs that plug into various places.
A lot of times, especially if I work on the passenger side of the engine, the "Plug" with 2 or 3 plastic lines will unseat from the AC box and cause strange engine problems including error codes, speedo jumping and bad shifting. Just plug it back in. Happens every time I change spark plugs.
ALso check any vacuum lines you can find to make sure they are in place and not cracked open.
I'm not a transmission expert by no means, but from what I have read here and other places, I would start by getting the speedometer working, the PSOM also supplies information to the computer and/or transmission. So most likely you trams issues are due to it receiving incorrect info..
Edit: Dang Jim did a better job explaining it.. and did it while I was posting this mess...
Ok I have another question about my issue. I noticed that when I pulled the VSS to replace it. There is grease or some substance all over the VSS. Is this normal? How does the VSS work inside the rearend? There were also some metal shavings on it.
Metal shavings are NOT good... The VSS works like a generator, there is a toothed ring on the carrier that interacts with the electrical coils in the sensor, each tooth produces one pulse.. The metal shavings are (for a lack of the correct term) shorting out the coils... If you pull the VSS out again and find more shavings you are going to have to pull the cover for an inspection....
I sure hope someone comes along that can explain what I trying to say...
i have a 1995 f250 and i some how sat on my roof in a way where it shorted out something and the intereior light did not work the bed light did not work the hood light did not work and the speedometer did not work and the odometer i could not see the numbers all it did was light up green. and all it was was a fuse in my fuse panel and i am good to go with that issue so far. beside s now i am also blowing blue smoke so i would check the fuses also. just to be safe i have a e40d also.
Update the garage told me it is the PSOM. 200 bucks to tell me what you guys have already told me. They want another 500 to fix it. That includes sending out my current PSOM to have rebuilt for 350 bucks. I just told them to go ahead and wrap it up. I can take care of it from here.