hi all. I have a 1989 E350, 7.3 Diesel with an E4OD, I believe. My spedometer cable, i guess, is getting bad, making my speedometer jump around, showing 10-40 miles less than actual speed. This is making my van shift strangely and when my pedometer "plummets" it shifts down. Everything seems to be better when I reach cruising speed, but is hell when going uphill at less than 40 mph. Since I am driving in lots of mountainroads, this is making me and my tranny mad. Is there anyway I can disconnect the cable at the tranny to stop this until I can get it serviced properly? If I do that, will it make the shifts even worse? If it is OK, how do I do it then?
Thanks in advance, Bjarni

 

An E4OD won't shift properly at all without a speed signal. Pull the cable and check the gear on the end of the cable, it may be worn and slipping on the drive gear which is part of the transmission output shaft.

 

I had the jumping speedo problem last week. Here is a test I did on my Vehicle Speed Sensor to determine if it was the sensor or the gear. Unbolt the sensor from the side of the tranny. Pull off the retainer clip and remove the gear. Check the teeth for damage and check the square hole in the center to see if it has become round. Have a buddy connect a variable speed drill to the square shaft on the sensor and run the drill at a very slow steady speed. Turn on the ignition. If the sensor is okay the speedo will show a steady mph reading. I had to buy a VSS from Ford cost $43. Good Luck

 

Thanks guys. I think I was not precise enough yesterday, and I forgot to mention that I have a fourwheeldrive. I crawled under the van and saw that the speedometer was connected to the outpout of my Borg Warner 1356 transfere case. Two wires were also comming out of there. I think I can remove the speedometer cable without removing the two wires. I was wondering if that should be enough, and the E4OD would be geting the speedinfo it needs through the wires from the gear/sensor in the BW Transfere case. I am pretty sure it is the cable itself which is the culprit, since I now hear a whirring sound from under the dash which started at the same time as the "jumping Speedo Syndrome".
I am not very good at this so I hope you forgive the stupid questions.
Bjarni

 

Bjarni, I never worked on a 89 but my 97 has an all electric speedo with no mechanical cable from the tranny just wires. A whirring sound from the speedo (if it's all electric) might mean your speedo gauge is breaking ?#@! I'm not much help here, somebody with speedo smarts needs to jump in. Good Luck

 

The speed sensor is the part that the wiring plugs into. It has the plastic gear on the inner end of it. I would still pull it out to check the drive and driven gears. The drive gear on the transfer case output shaft is replaceable. I have seen many drive and driven gears worn down to the point that they barely contact each other. You may need to replace either the sensor, the drive gear, the driven gear, or even all three. You might even just have a bad cable.

 

Thanks guys for your input. I do have a mechanical cable for sure. Tomorrow I am going to disconnect it and se if that is enough to make it shift better. I am thinking that perhaps a bad mechanical cable is slowing down the gears in the transfer case. This is a minor thing to do and since I am in a place where I can not get spares I nor service, I will hope that I can limp home aprox 500 miles.

 

Hi guys and thanks for the help. It turned out to be the plastic "gear wheel" that goes into the transfer case. It was worn out. It was a lot easier than antisipated to replace it. The gear (also plastic) in the transfer case seems alot less worn.
Anyway, for your information. If you have a mechanical cable to the speedometer, it is OK to disconnect it from the unit that goes down into the transfer case; the E4OD gets the info through the wires from the transfere case directly, not through the speedometer.
Bjarni