my abs and brake dash lites are flashing very erratically.speed-o reads correctly.cheched connector on top of diff.seems good.lite will stay off then will come on as soon as i shift into any gear. rear speed sensor?

 

welcome to dtr It would help if you filled out your signature so we know what year,truck,auto ,,drive train, and any mods. but from the sounds of it sound like a loose or corroded connection