i replaced the rear pinion seal a year ago and just recently it started leaking really bad over night. i just replaced the rear rear u joint and also one the the leaf spring shackles broke. it wasnt leaking til after i replaced the shackle. is it common for the seal to go bad in just a year ? is it possible that i messed something up when i replaced the shackle and mounting bracket so maybe the rear end isnt setting level? i dont have a clue im kinda stumped here.