My speedo has jumped occassionally in the past; I'd see it peripherally, then when I'd stare at it there would be no jumping.

Now sometimes I'll look down and it'll be on zero, odo not moving either, then it'll start jumping and then finally leap up to my present speed (which I was probably better off not knowing).

Sometimes it'll work all day and then stop working in the middle of a trip.

Checked the OBD and it did have a code that speed signal not being received.

So I check my Bentley and it's saying that if I replace the sender I have to shim it properly; it's sounding like a PITA job.

Or is Bentley being its usual overly fussy self, and I can just replace the sender?

A side worry is that I've been having a wheel bearing-sounding noise for a long time, and it persisted even after I repacked all four wheels, which all looked to be in great shape (althought the Amsoil grease in the fronts turned to watery grease pretty quickly).

What I was wondering is; if the right rear bearing was failing could it pull the sensor wheel out of alignment enough that no signal would be sent? One time the speedo came back right after I made a hard leftie.

I'll leave all the other issues to other posts, but will mention that last night my temp gauge was at zero for a while, even though I had nice warm air coming out of the vents,and on the way down a long hill it went back up to normal, slowly.

I mention this because I also wonder if it might be an under-dash electrical issue, but I did unplug/replug the speedo cable several times and it didn't affect the speedo behavior (worked for a while, then did it again last night.