Speedo is going haywire!

[Dezertpilot]

So my Autometer Speedo guage was working fine for the past 1.5 yrs. Now when I get to 60 mph the speedo needle jumps alot back and forth. It does this till 80 mph then its fine. When I slowdown or downshift to a slower speed it still sticks at 60-75 mph but then will all of a sudden drop back down to 0-15 mph. What could be the problem? Is there a sensor that is going bad? Is a sensor dirty? I did a quick look around and saw nothing around the trans that seemed to be the culprit but that was real quick cuz I am in my night clothes. The vehicle is a 1986 Toyota 4runner with a tranny that is a 5 speed but I dont know what model it is. And the motor is a 1987 Supra non-turbo. And I believe it is a mechanical speedo not an electronic one.

[sickrick]

I have found that soon after this starts to happen the speedo cable breaks. I would hook the speedo up to a drill and spin it if it reads steady; replace the cable.

[Dezertpilot]

Ill just replace it. Do you know what a new one would cost and can I usually get one say at a local parts store than the stealership? Its easy to replace and no special tools right? Oh and what exactly does it look like? I seen like 2 cables on the trans.

[Dezertpilot]

Also how do I recalibrate the speedo to compensate for the 4.88's with 33's? Is there a way?

[Bryan_D]

Check the gear on the speedo or on the speed sensor. I have had this happen in the past.