Problems with gear change
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Problems with gear change
The truck is a 98 F150 4.6 5spd. It is lifted and has 33" all terrrain tires installed in the winter and 35" mud tires in the summer. The truck came with 3.55 gears but with the tires bogged it down to much. We changed to gears out with 4.56 motorsport gears. This ratio works great in this truck - very good punch, don't have to shift out of fifth for every hill, it doesn't rev the engine too much on the highway, either. The problem isn't in the ratio selection, its perfect. The problem is the speedometer seems off, but I'll have to check it to find out how much. The truck shuts down at just a little over 80mph now. I thought that the speedometer was run by the speed sensor in the rear differential like a 92-96 Fseries, if that is true then a gear change shouldn't effect speedometer - the speed is calculated by ring gear speed and stock tire diameter. SO - if the speedometer isn't effected by the gears, it sure is effected by the tires. But why does the truck shut down at 80?
The tires should cause the speedometer to read lower than actual speed.
I'll know more about the accuracy of the speedo tomorrow, I'll time it between mile markers on the interstate with the cruise set on 60, then I'll know how far off it reads and go from there.
The tires should cause the speedometer to read lower than actual speed.
I'll know more about the accuracy of the speedo tomorrow, I'll time it between mile markers on the interstate with the cruise set on 60, then I'll know how far off it reads and go from there.
