E4OD speed sensor?

[Ole BlackBetty]

ok, I looked at all the electric connections on my transmission, 4x4 I could find anything that looked like a speed sensor on the tranny. I do have an ABS speed sensor on rear diff.

 

[Nero]

If I remember right, the sensor in the diff is used for the e4od in the 1994 year. What faults are you getting?

 

[Ole BlackBetty]

If I remember right, the sensor in the diff is used for the e4od in the 1994 year. What faults are you getting?

speedometer bouncing all over the place at higher speeds

 

[Nero]

Is the transmission shifting just fine still? Probably a tired speedometer gauge

 

[Ole BlackBetty]

nope not shifting at all.

 

[Ole BlackBetty]

found this on Google search and wanted to check all alternatives before overhauling transmission.

An E4OD transmission with reverse but no forward gears typically indicates a problem with the forward clutch pack, which is likely burnt up. This can be due to insufficient rebuild quality, incorrect gaps, or other internal issues. Other potential causes include low line pressure, a faulty valve body, or a damaged speed sensor.

Detailed Explanation:

• Forward Clutch Pack:
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  The most common reason for the described issue is a burnt-up forward clutch pack. This can happen if the transmission was rebuilt with insufficient attention to detail, such as not checking proper clearances or using low-quality components.
  
  
• Low Line Pressure:
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  Low line pressure, often due to leaks or faulty components, can also prevent the forward clutches from engaging properly.
  
  
• Valve Body:
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  A faulty valve body, or its associated components (like solenoid O-rings), can cause incorrect hydraulic pressure to be sent to the clutch packs, leading to a lack of engagement.
  
  
• Speed Sensor:
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  Although less common, a faulty speed sensor can send incorrect signals to the PCM (Powertrain Control Module), which may prevent the transmission from shifting into forward gears.

 

[Ole BlackBetty]

my speedometer was bouncing erratically for about a week before trans lost all foward motion.

 

[u2slow]

The E4OD depends on the diff signal being proper to shift properly.

I worked at a shop 25 years ago where we changed the trans for acting funny. That fixed nothing. It turned out it was the diff tone ring that was damaged.

 

[IDIBOBS]

Trans uses tone ring in the rear axle. Speedo uses a cable to the trans/tcase. The 2 are independent of eachother. My 94s Speedo does not work at all. Plastic gear in tcase is trashed. Trans shifts perfectly.

 

[Nero]

Pretty sure 1992+ they switched to a digital speedo driven by the vss off the diff for the E4OD, since the wiring sends the speed signal to a digital processor in the cluster, then the cluster sends the processed signal to the transmission controller.
If you have a mechanical drive cable, chances are your truck has been modified. Part of the reason why using a t case from a newer truck is difficult on an older one, no speedo drive gear or hole.

To loop back around, if your transmission isnt shifting, do the usual checks. Fluid level, color, check for codes and we can help from there.

 

[u2slow]

Pretty sure 1992+ they switched to a digital speedo driven by the vss off the diff for the E4OD, since the wiring sends the speed signal to a digital processor in the cluster, then the cluster sends the processed signal to the transmission controller.

I thought the diff signal fed into the PCM, and then processed/routed for speedo, trans, ABS.

This is just my loose recollection from when I had my '97 E350... I was messing around with changing the gauge cluster.

 

[Ole BlackBetty]

I has no cable connected to the transmission or the transfer electric wires. Besides the my plug into the cellular body is an electrical connection on the transfer page with 2 wired. Which I believe is the full will drive indicator. There are no other sensors on my transmission or transfer games.The one in the differential is called an a bs speed sensor

 

[Ole BlackBetty]

Voice text didn't work very well

 

[Nero]

The early versions of the e4od that had the OD disable button on the dash used a mechanical speedo cable and was on the transmission, or transfer case if you were 4x4. The later models, 1992+ went digital when the trucks went to the obs body style and the new digital clusters. @u2slow I believe you are correct. Its the engine speed sensor that goes to cluster, then to the TCM.

Speed source on the later models is the rabs diff sensor.

 

[Ole BlackBetty]

That's what I have 1994