This has been going on for months. Speedo will jump up to the right speed and then rest at zero for a while. Over the past 3 days I've only recorded 9 miles. I'd really like it to work again. I'm almost sure its the instrument cluster, which I have a spare for. But where in hell does it get it's reading from? Considering I just did a 5spd swap and there is no speed sensor in the trans that is hooked up it would have to be the ABS system right? Not the ABS computer, already swapped that out. Also in the same system but may be unrelated, my rear diff lock fails to engage. All of this has been in non sequential order so... ABS light on with no code (Jan 2011) Speedo going on the fritz (March 2011), diff lock blinking and never engaging (July 2011) and just did the trans swap.

Any ideas? Hate to rip the dash apart to throw in the cluster if there is a simple fix.

Honestly, I have no idea but I'm inclined to think it has something to do with the swap as opposed to the cluster. My guess is speedo and odometer work off of a sensor in the trans. The days of a cable in the trans are long gone but a sensor and plug is still around. Have you looked into the vehicle speed sensor at all?

Makes sense but then it doesn't. It started moths before the swap. And it is still picking up an accurate speed reading from somewhere on and off.

I have a somewhat similar issue, if I hit a big pot hole at speed my speedo drops to zero. Once I come to a complete stop and start driving again it returns to normal. No idea.

It's the ABS speed sensor. Picked up metal trash from my passenger front bearing grenading. Changed bearing and cleaned sensor and all is good.

, beat me to it ;-)