No,it didn't happen suddenly...2 days ago i was working on my car.An audi A4.I was trying to get the damn cat bolts off.One snapped and i got hurt.From my nerves at the moment i gave 2 hard punches at the front differencial.Off course the differential didn't feel a thing,but my right hand pumped u like a balloon.I didn't feel any pain except when i was lifting my 2 last fingers.I thought it was nothing so i let it that way.My family and my girlfriend,insisted to go to the hospital just to be sure.So,i went today and made an x-ray.Doctor said it's not broken but cracked...I will post pics when my new phone arrives.And i'm getting new bearings tomorrow with hex screws