transmission manufacturer combines the master mapping the shaft mapping and the sensor mapping at 70 to produce a production mapping one way to accomplish this is to compute differences between the master mapping and the sensor and shaft mappings respectively and add these differences to the master mapping after the transmission is assembled at 72 the production mapping is entered into the transmission controller at 74 this production mapping at least partially compensates for the part to part variability of the sensor and the shaft if there is interaction between the sensor variability and shaft variability the production mapping does not capture that interaction also if the sensor and shaft mappings are produced at the component manufacturing facility the production mapping does not compensate for any changes that may occur while the components are in transit the process may be modified to compensate for changes in shaft magnetization that occur in transit by doing the shaft mapping at the assembly facility using a portable tester like the tester illustrated in fig4 tester 80 includes a pedestal 82 sensor housing 84 and a test controller 86 the shaft 30 is placed into the pedestal 82 such that the carrier rest on thrust bearings 88 a ring gear 90 may be fixed to the pedestal a shaft 92 with a sun gear may extend into the pedestal from below the output shaft is positioned radially such that the planet gears mesh with the sun gear and the ring gear sensor housing 84 includes the master sensor 40 u2032 bearings 42 u2032 and seals 44 u2032 the sensor housing 84 slides over the production shaft 30 sensor housing rests on pedestal 82 to locate the master sensor axial with respect to the magnetized region 38 the wiring harness of the.