I am not a mechanic, never pretend to be - if someone needs help, i'll try, with instructions - anyways - i blew out my unit bearing last weekend, 2nd in 2 months. i went cheap the first 2 times, but not anymore. do it right the first time! i broke 2 1/2" drive ratchets trying to loosen the axle nut - 1 is going back to sears! couldn't loosen that damn axle nut for nothin - went to pep boys to buy a breaker bar, but decided to try their cordless impact wrench - holy moley! it worked like a charm - i put the last unit bearing on at 150 lbs (my bad, should be 175) so this cordless impact driver did what i couldn't do with a 1/2 " drive & a cheater bar in about 4 secs