I had a weird thing happen to me on the way to work today. My speedometer was not reading correctly. I was going along about 65 or 70 MPH but the speedometer was jumping around from 60 to 75 then at one point dropped down to 45 and jumped around there then back up to 70 mph. it jumped around for 15 to 20 miles then it started working correctly. Also while this was going on the overdrive light on the gear shift was flashing. Any ideas?

 

What year is your truck? If 97 or 98 your speedometer gear is probably bad. 10mm socket, it's located on the driver side transmission tailshaft. Pull it out, probably teeth chewed off.

 

Bad VSS for your year.

 

My truck is 2001 5.4L
What is VSS?

 

Ok vehicle speed sensor. It looks like it is just a mag pick up. I will attempt that thank you. It might have gotten wet or something from all the Harvey rain. We didn't get it as bad as most though.

 

I got my VSS in last night and got it installed fixed the issue. Thank you so much