Wheel Bearing Replacement Procedure

[blue thunder]

I just had my left rear wheel bearing replaced(328.00). I had read it on here and maybe another site that one of the reasons for the short life of the bearings was the grease that came with the part was not cleaned off and replaced with a better product. I brought this up to the mechanic at the dealer and he disputed this saying it was high temperature airplane grease which he was taught in tech school. I called another dealer ironically he used to work at and the mechanic there verified what he had said so I went ahead with the service. Does anyone have any real facts on this subject. Others may learn from this as well. An unrelated item can someone tell me the location of the MAF unit. I want to soak it in white vinegar for a few hours as I read in another thread. Thanks to all.

Mike