Front axle bearing humming noise - help!

[tpazz]

I have a 02 Envoy XL (4x4). I had some front end humming noise a while back (vehicle had 120,000 KM at the time) noise got louder when I turned right - changed out the left hub bearing - all OK. At 160,000 KM same noise, this time other side- changed out the right hub bearing. Now I have another humming sound that doesn't appear to change turning left or right - starts at about 30 KM/h and gets louder the faster I go. I am pretty sure that it is not coming from the hubs - as they are relatively new. Vehicle currently has about 168,000 KM. I think the last bearing noise was masking this new noise. I have pulled off the wheel, brake calipers, rotors and spun the front axles. Left side is stiffer than right but I don't hear any grinding. Front axle oil is at the proper level though its quite dark but it doesn't appear to have metal filings in it. I am suspecting its the left front axle bearing. From this forum, it appears that the right side is an easy change - but the left looks like its a real ass pain. Before I get into this, does anyone have any ideas on how to confirm it is indeed this left bearing? and any tips to changing this out.

Thanks in advance