Try this, when the SET light is flashing, with the key off, pull the fuse for the gauges. The fuse block on the lower right side of the dash, right column (closest to the door) 3rd 10amp fuse from the bottom. This will kill all power to the cluster and reset it and will tell you if it is in the gauges or somewhere else in the truck, like the speed sensor, ABS, etc......
Yes, if there is a problem with the cluster and the ECU see's a big enough difference in speed info, it will cause the same problem you have now. This happens if i try to set my Hypertech Speedo Reclabrator to far out of spec. IE: Set for 26" DR's and install 32.6" stock tires with out resetting.