My speedometer has become somewhat bouncy at speeds 30 and up. I have also noticed a bit of shifting issues which I have learned may be related. I would like to replace the vehicle speed sensor but have not been able to learn if it is in the transmission or drive axle. The internet shows it both places and sometimes only in one location. I am also somewhat confused as to what it looks like. I believe there is some misinformation on line regarding this. I am sure however someone here can tell me right away what the best process is to replace this.

VSS 1990 F-250 E4OD 7.5

Thanks StrayKat

 

Your truck uses a cable driven speedometer/odometer. Your speedometer issue is a mechanical problem. Inspect the drive/driven gears. Could be as simple as lubricating the cable.

There is a VSS is in the tailshaft or transfer case to provide vehicle speed input to the computer and Speed Control system. If the VSS is in line with the speedometer drive cable then I would suspect a gear wear issue.

The rear axle has an axle speed sensor for use with the RABS (brake system).

 

Your VSS looks like this:



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Thanks for the Picture- Was sold the wrong part for sure. I know where that is and thought that was it. Thanks a million

 

RLA2005..I will put some lube on the cable and see if thats all it needs. In regard to the gear wear issue is that something a VSS replacement would correct or is that internal to the transfer case? Also have you heard of that maybe causing a shift issue - it is only a minor issue at the moment and really only notice it driving around town. Trying to be proactive ...

 

A replacement VSS does not come with a gear. There is a corresponding drive gear inside the transfer case. Either or both can be worn.

Since the VSS is inline with the speedometer drive cable and you are experiencing shifting/speedometer issues I would seriously take a look at the gears and as a preventative measure lube the cable thoroughly.