I have a 2005 f250 v 10. I just put 4.88 gears in the front (Dana 60). Got it back together and now the abs light is on.. Any ideas?

 

Sensors plugged in?

 

I assume you already had 4.88 gears in the rear?

 

Check if the sensors are plugged in correctly, and then make sure, if you took the sensors out of the wheel bearings while you were doing the work, that they are fully seated back into the wheel bearing housing.

After checking all that and you still have an ABS light, pull the connector for each sensor, connect a digital volt meter set to AC volts to the pins in the connector and spin the wheel as fast as you can by hand. You should get around .2-.3 volts from the sensor. If you get no voltage, the sensor or the wiring is bad, or the sensor isn't close enough to the tone-ring inside the wheel bearing to register anything.