Hello, I have a 96 E-350 15 passenger 7.5 460. The speedometer is bouncing and having shifting problems. I changed the vss, didn't change anything, I changed the psom with a refurbished one. Still having the same problems. Just realized I have a 4w abs system. Should the vss I installed have been a factory ford parf? Is it possible the abs sensors are causing the problem? Are there any other sensors I am missing? I live in the mountains and haven't been able to get it down to get a code read on it. I recently changed to a bigger tire, could that be causing it to shift in and out of overdrive? Also noticed the brakes pulling when it has shifting issues. Any ideas would be helpful, I have three kids and need this van to be working. Thanks in advance