1992 Ford Tempo Transmission works intermittanty

175,000 MILES • 4 CYL • FWD • AUTOMATIC
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JANKETEMPO
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  • 2 POSTS
Ive been driving my ford tempo thru the harsh minnesota winter and have had no problems with it at all. now that the weather is gettin better the engine is able to warm up to regular running temperature a lot faster. as i start out in the morning (the engine is Cooled off) it starts everytime and shifts just fine as well. the speedometer is a little jumpy vibrating side to side aprox. 2 miles per hour in both direcitons. once the engine reaches a warmer running temperature (not to the point of over heating or even getting too hot) the speedometer begins to not read the vehicles speed anymore and drops down to read zero and the tranny responds and shifts into a much lower gear. someitmes it recovers for a second and the speedomer jumps back to life but only for a second.

Once the engine has cooled down again the tranny shifts alright and the speedometer reads again. I only need the car to run for another month due to me enlisting in the US Army and i ship out at the end of may.
but right now im restriced to a 10 mile radius around my house.

I replaced the speed sensor (which was broken)

did i install it wrong? and why is this only a problem when the vehicle heats up?
Apr 28, 2009 at 2:25 AM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
VSS sends info to speedometer and ECM, you may have installed it wrong or have the incorrect part, or it may be problem with ECM.

Also check fluid level in trans (engine running) in park.

Change trans filter and look for any metal particles on magnets at bottom of pan.
Apr 29, 2009 at 11:27 PM
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JANKETEMPO
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The fluid level is correct when running and in park it isnt the right color tho its alot darker than it should be. I will verify that i installed the new sensor correctly are their other things?

I have been told somthing about Gear drive connected to the speedometer may be worn out?
Apr 30, 2009 at 2:08 AM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
Some VSS (vehicle speed sensors) are driven by a plastic gear, which can break, loose teeth and give bad readings.
Apr 30, 2009 at 11:59 PM
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