I replaced the Vehicle SpeedSensor that’s on the tail shaft of gear box nothing changed. I would like to know if there is another sensor that affects the speedometer possibly inside the transmission ( 4L60E ) ? Also thought about the wheel speed sensor does it affect the speedometer ? The truck hasn’t thrown any check engine codes. Now this I’m not sure about but transmission may be getting hot because of this as my starter has started to drag when cranking truck when engine is hot , may just be time for a starter , I haven’t driven it enough to be sure about the transmission temp. One more thing if this leads me to a wheel speed sensor how do I tell which one it is? I have the original size tires and wheel on truck.
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Your vehicle has a module called a VSSB (vehicle speed sensor buffer) or a DRAC (digital ratio adapter controller). This is a small circuit board inside a non-waterproof snap-shut case that's usually in the vicinity of the PCM. Possibly behind the glove box.
The module has permanently soldered jumpers that establish a ratio between the number of pulses detected by the vehicle speed sensor and the pulses sent to the PCM. The pulse ratio that's used depends on the gear ratio in the differential(s) and the circumference of the tires that were installed at the factory. The module's pulse ratio can't be easily changed; it would require cutting circuit board traces and/or soldering jumpers.
However, aftermarket modules (replacement VSSBs or DRACs) with DIP switches are available to easily calibrate the speedometer for different tire sizes or differential gear ratios. Useful when changing from highway tires to mud tires, for example.
As far as I know, wheel speed sensors have no effect on speedometer readings, as their pulses feed the ABS module.
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