I'm confused...again...
Does the car have cruise now, or has it been removed? The speedo cables for cruise/non-cruise are different, since cruise cars have two cables. The cable from the trans to the cruise transducer has a threaded barrel fitting on both ends.....cables for non-cruise have the barrel fitting only on one ends, and the other ends is a female slip-fit into the speedo head.
Does the transmission end connect directly to the trans speedo gear housing, or does the trans have a 90 degree adapter on it that the cable attaches to?
There are two gears on the trans that operate the speedo....one in the gear housing, and the drive gear on the tailshaft of the trans. BOTH must be in good shape.
If you connect the cable to the speedo head in the gauge cluster, can you spin the cable on the trans end and see the gauge move? If so, then one or both of the trans gears(or the adapter, if present) are at fault.
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Joel Adams
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