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Discussion Starter #1 (Edited)
Does anyone know how to modify the VSSB (vehicle speed sensor buffer) on a 1995 to correct for the change in gear ratio and tire size such that the speedometer, ABS, transmission shift points and cruise control will function properly?
 

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Discussion Starter #5
Thanks for the link.

I presently have the VSSB accuracy now to my satisfaction. I originally measured the tires rolling circumference off the truck, calculated the pin out and re-set the jumpers. This made a vast improvement in my shift points and improved the speedometer accuracy, but I was approximately 4-6 mph too fast.
I subsequently measured the rolling circumference on the truck as well as obtained the rotations per mile from the manufacturer. The rolling circumference calculated from the manufacturers rotations per mile was the most accurate in my instance. It is interesting the significant effect speed has on the rolling circumference.
I am now within 1-2 mph at speeds less than 50 mph and accurate in the 60-80 mph range.
In my one time experience the rolling circumference measured with the tire off the vehicle was an overestimate.
I just elected to move the individual jumpers as opposed to the DIP switch install, as 6 pin DIP switches would have to have been ordered.
I had previously installed a Jet Performance Tru-Speed, but IMO all this unit accomplished was to correct the speedometer signal, having no effect on the shift points, cruise control and ABS. The wiring diagram in my Chiltons manual seems to support this.

Cordially, Glenn
 
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