Pino2234
Full Access Member
My 86 Ford F350 has 37s on it with 3.55s. The speedometer was way off and I wanted to stop using my gps to calculate fuel mileage bc now I have 2 trucks. Ford didn't make a driven gear for the speedo cable for my application because of my ratio and tire size. Its like i have overdrive with my t19. I currently have the 16 tooth driven gear (the lowest). I searched and found an 8 tooth drive gear for the transfercase that I installed. I think it had a 6 tooth drive gear before but I'm not sure.
So with my 16 tooth driven gear and 8 tooth drive gear I should be right on.
So I installed it and the tripometer seems to be on. In 29 miles the GPS says I went 29 miles and my truck says 29.2miles. But the needle is off. When the GPS says I'm doing 40mph my truck says I'm doing 45mph. And it's gets worse or better as I change speeds. It could vary from 1 - 10mph difference.
Now for my 2nd truck:
My 85 dually just has 33s on it and the speedo is way off as well. The speedometer is really slow compared to the GPS so you would think that the tripometer would be slow as well. But it's not. If I go 200miles on my GPS, my tripometer reads around 230miles even though the speedometer on the truck always reads slower than the GPS.
Also does anyone know the relationship between the speedo cable, the needle on the speedometer, the tripometer, and the odometer?
I'm just trying to get both trucks right on.
So with my 16 tooth driven gear and 8 tooth drive gear I should be right on.
So I installed it and the tripometer seems to be on. In 29 miles the GPS says I went 29 miles and my truck says 29.2miles. But the needle is off. When the GPS says I'm doing 40mph my truck says I'm doing 45mph. And it's gets worse or better as I change speeds. It could vary from 1 - 10mph difference.
Now for my 2nd truck:
My 85 dually just has 33s on it and the speedo is way off as well. The speedometer is really slow compared to the GPS so you would think that the tripometer would be slow as well. But it's not. If I go 200miles on my GPS, my tripometer reads around 230miles even though the speedometer on the truck always reads slower than the GPS.
Also does anyone know the relationship between the speedo cable, the needle on the speedometer, the tripometer, and the odometer?
I'm just trying to get both trucks right on.