speedometer sticking

Out of the frigging blue my F$#@$%in speedometer on startup goes to 120 and stays there. Took the dash apart, reset the needle to 0. All good for about 100 miles.

On the way home tonight get off the highway, all good stop at the light all good. Accelerate go up the hill turn and the speedo goes to 70MPH and sits there.

I did change out the trans about 500 miles ago. Any idea if I could of F-ed up a pin going to the side of the trans that would cause this????

Or is it one of those f-in TSB's that have expired about 5 years ago and 50,xxxx miles and I'm out of luck with close to 129,xxx miles on the truck???

I do cluster repair. $20 and shipping both ways and you're good to go.

Follow this write up and fix it yourself.
http://www.ls1truck.com/forums/elect...e-cluster.html

Thanks to you both, This will be an easy project to get done on my own, but if I F%^k it up I'll be reaching out to Duct_tape123! Just need to get the part # for the speedo stepper motor now.

x25 168 is the part number.