Output speed sensor or vss

At actual speed of 40 mph pcm and speedometer say I. Doing 110mph and I double checked with a scan tool and since pcm is getting that info truck hits speed limiter at 110mph so I can only do 40 before it hits speed limiter my question is where is the sensor located at on the tranny that feeds the pcm that feeds speedometer mph and would the abs speed sinsor have a part in how the speedometer reads my truck according to the vin number has a 4r55e should the speed sensor be on the tranny or tail shaft housing