Hi guys, it's been a while since I've posted anything......but I have a puzzle for anyone who knows something about speedometers.
Background - I have a 65 Mustang Coupe, 302 V8, modern T5 manual transmission. Car was finished about 5 years ago, speedometer functioned fine for about 3 1/2 years, finally starting behaving erratically, did not behave normally, would read 60 mph standing still, stick at high speed etc. The speedometer appears to be the original one....stamped FORD.
This weekend I finally got around to doing something about it. I checked the cable, seemed ok, no apparent binding, plastic gear on transmission end looked like new, so I replaced the speedometer with an aftermarket one I had. Put it back together, speedometer now rises normally with increasing speed and falls as you slow the car down. The trouble is that is seems to indicate about double the speed that I am doing.....so if I an traveling at about 25-30 mph, the speedo shows about 60 mph.
The only thing I changed out was the speedo.......what is going on? Could an aftermarket speedo have different gears from the stock speedo? Is there some kind of adjustment on the speedo (don't think so)? It it something electrical (don't think so as operation seems to be purely mechanical)?
Thanks in advance.
Background - I have a 65 Mustang Coupe, 302 V8, modern T5 manual transmission. Car was finished about 5 years ago, speedometer functioned fine for about 3 1/2 years, finally starting behaving erratically, did not behave normally, would read 60 mph standing still, stick at high speed etc. The speedometer appears to be the original one....stamped FORD.
This weekend I finally got around to doing something about it. I checked the cable, seemed ok, no apparent binding, plastic gear on transmission end looked like new, so I replaced the speedometer with an aftermarket one I had. Put it back together, speedometer now rises normally with increasing speed and falls as you slow the car down. The trouble is that is seems to indicate about double the speed that I am doing.....so if I an traveling at about 25-30 mph, the speedo shows about 60 mph.
The only thing I changed out was the speedo.......what is going on? Could an aftermarket speedo have different gears from the stock speedo? Is there some kind of adjustment on the speedo (don't think so)? It it something electrical (don't think so as operation seems to be purely mechanical)?
Thanks in advance.