After driving my '57 for the past two weeks without a working speedometer, I decided to get to the bottom of it tonight. With the car jacked up, running in gear the speedo cable is turning clockwise but the speedo actually has to be spinning counter-clockwise for it to work. If I put the car in reverse the speedo works. Has anyone had this problem and found a solution for it? Is there anyway to reverse the drive inside the speedometer? The motor and trans are not original. 351/Tremec trans.
ford made different gears for the trans, the cable would go into the tailhousing from different sides and angles on different models. so you probably have the wrong "handed" drive/driven gear in the trans. they make them both ways....
Yep. Abseloute worst case, you need to hit the junkyard for a speedo drive gear that was on the same side as stock '57 Merc but was in the same type of trans you're running now. Or find a cruise control unit you can reverse the shaft going to the speedo, in.
If nothing else works, you can buy tach drive gear boxes that will reverse direction. Try Aircraft Spruce as a source. They are on-line. Just google them. The only trick might be adapting the speedo cable to match the tach cable fittings.
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