1999 Peterbilt 379 Speedometer Bounces

Ok on my truck when you put it into gear from neutral, the speedometer will jump from 0 to whatever , 30 40 50 , also the speedometer is new the old one went out , also it only reads half of my speed , also the sensor is new on the drive shaft . Anyone have clues ! Thanks

Detroit 60 12.7

 

It is tight checked it

 

Boss man crawled under it over the weekend and checked it what he said not sure how he did . Just said it’s ok

 

No cruise no Jake’s , been trying to figure that out computer says all sensors are working and we checked clutch and brake sensors they are good

 

So could that stop my Jake’s and cruise ?