Hello I have a 96 Ford E-350 7.5 15 passenger van . Speedometer jumping , shifting hard, I changed the vss, didn't use a ford part, symptoms improved but didn't go away. I changeed the psom with a refurbished one, ran much better 90 miles in, speedometer still jumping, now shifting in and out of overdrive at highway speeds only, in town speeds shifts fine but speedometer still jumping. I recently replaced the front rotors, should I have changed the abs sensor? When I replaced the front hubs I noticed teeth on the inside of the hub, are those tone rings and is that where the abs sensors are? Any information would be helpful, I use the van every day and can't have it out of commission. Thanks in advance