Help Please Speedometer problem

[richemmers]

I am new here but I need help

I have a 01 f-350 ext cab 4x4 7.3 auto

The speedo wasnt working until i got to 40 mph, and the abs light was on.

Well I replaced the vss and the speedo works now until i get to 40 mph and it wont go any farther, but the truck runs fine.

I recently changed tires from 315/75/16 to 285/75/16

I also replaced the inner-tie rod.

Before i did all this the speedo would work after 40 mph but not before it got to 40

also the o/d light does not come on

I am leaving for deer camp in 6 days, and want to fix this, or i have to use the gps for speed

[woodnthings8]

Your speedo gets its signal thru the ABS module, it gets signals from the rear vss sensor. If you have an ABS light you probably have other issues.
You o/d light can be burnt out, does it shift into o/d and can you cancel it with the button?

[richemmers]

the abs light went out as soon as I replaced the rear speed sensor (vss)

[woodnthings8]

Here is what the manual says about the speed signal;

The instrument cluster is hardwired to the four wheel anti-lock brake system (4WABS) module. The instrument cluster micro-processor monitors the VSS data from the 4WABS module and commands the speedometer with a corresponding movement of the pointer. The vehicle speed signal is generated by the rear anti-lock brake sensor and sent to the 4WABS module. The 4WABS module sends the vehicle speed signal via circuit 679 (GY/BK) to all systems that require a vehicle speed signal input.