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Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 33460
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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I have a 1993 ford e-250 cargo van. The problem being that

Customer Question

I have a 1993 ford e-250 cargo van. The problem being that the transmission no longer shifts properly. I noticed the speedometer quit working-shortly afterwards it wouldn't shift into 3rd gear w/o manually dropping gearshift down into 2nd gear then back up into 3rd,then it would shift into 3rd gear and into o/d like it was supposed to. But was able to keep it goin done the road. It's now requiring a higher and higher rpm to manually get it into 3rd gear. I'm wondering if it's not able to sense what speed its at in order to shift properly as the the speedometers not working. Can you guide me as what to do to correct this problem.
Submitted: 1 year ago.
Category: Ford
Expert:  Ron replied 1 year ago.
Hello and thank you for your question, My name is ***** ***** I will assist you today.
The most common cause for the loss of speedometer operation on your 1993 is usually caused by a failed Differential Speed Sensor located on the top of the rear Differential and when it fails it will cause the transmission to shift late and hard. The other cause can be caused by a failing PSOM (speedometer cluster assembly) which can also cause late shifting . I would start first with checking the Speed sensor. The resistance should indicate a reading between(###) ###-####ohms. If the resistance checks okay then suspect the PSOM has failed. See the test steps for it in the link below. Copy and paste the link to your browser to open and view them.
https://dl.dropboxusercontent.com/u/104923897/POSM%20testing%20Jul%2013.pdf