I have a 1999 Outback wagon with 287k miles and auto transmission. Recently the speedo has begun acting whacky at indiscriminate times. The needle will suddenly drop to zero while I’m driving it, and then it will just as suddenly pop back up to register the speed. There’s no rhyme or reason as to when it will drop or when it will re-register. It did it once a few weeks ago, and then once again the week after. Now it’s doing it about 2 times a week. Any idea what’s causing it? Is it going to become more frequent until it does it all the time? Thanks for your help.
The most likely cause is a failing Vehicle Speed Sensor (VSS), which is attached to the transmission. Of course, at 287K the speedometer itself could also be going, but I’d suspect the VSS first.
Thanks for the insight. If it is the VSS, is that something that could be accomplished without the “help” of a professional mechanic, or would the tranny need to be pulled?
Should fall into the do-it-yourself category. The VSS attaches to the transmission. Not sure exactly where on this car, but they’re usually mounted on one side or the other of the transmission. No need to pull the transmission. You will need to get under the car, though.
Jack stands or ramps. Don’t crawl under a car supported only by a jack.
A Haynes manual would probably be helpful for something like this.