Sorry for delay but problem solved. Took it to Peterbilt and the speed sensor ring was loose. Cost me $800.00 and two days later truck got hit by...
I have a 387. The switch is located under the cab on the frame.
I will
The speed sensor is new. The transmission is oil wet at the end where the yoke is.
When I start running the speedometer starts going up and down until about 45 mph. Then it works good. For some reason my Qualcom Elog is giving me...