QUOTE (rsquared @ May 17 2010, 09:17 PM)
There may have been some ware marks in the axle, that is possible, but if the seal was fine...why did they replace it? A more likely explanation would be either the seal wasn't the right one, had a defect, or it wasn't installed correctly.
I hope that takes care of it for you.
I don't know of anyone that re-uses a seal when repairing a leak like that, whether the seal was still good, bad, or indifferent, it's so cheap in the scheme of things that it's not worth taking a chance on the old one.
The seal could have been installed wrong (not hard to do if the installer was inexperienced or in a hurry), it could have had some sealant inadvertently smeared on the rubber during installation, it could have had a manufacturing defect in it, etc., etc., but once you pull the seal, it's so distorted you can't re-use it even if the rubber was still good.
The axle shaft could have had a groove worn in it from the previous seal, it could have had a defective finish, it could have been "bad metal" (pitted, poor quality, but this would be extremely rare to have the odd shaft of poor quality steel), but the machinist that polished the shaft should have been able to spot that type of problem. I would suspect that the groove was overlooked and caused the second leak, I have a chev impala that's prone to that type of wear on the harmonic balancer and the replacement seal kit often comes with a micro sleeve to repair the grooved balancer (I just changed the seal and repaired the balancer to stop a front seal leak this last weekend).
Another leak would certainly drive me to replacing the shaft as well as the seal again.