Possible Tranny going out?

I have a 2000 Montana that has a roar coming from the passenger side. It seems to get louder as the van goes faster. I thought it maybe the wheel bearing but the roar is a lot louder than a wheel bearing I have ever heard of. I jacked the van up for futher inspection and it sounds like its coming from the passenger side output area. This problem has went on for about six months. Is it possible that the bearings of the output could be going out? Neither of the wheels has any play and neither half shaft has any play in it either. Does anyone have any ideas?
Thanks SSgt David White US Marine Corps

I would still consider wheel bearing until proven out, since it is a "most probable" event.
NOrmally, wheel bearing noise will get worse turning one direction, and less in the other direction. Such behaviour definitely points to failed bearing.
In doubt I jack one front wheel , parking brake applied, block other front wheel as necessary to feel safe, and I run the engine in drive up to 30 MPH max: the other wheel on ground, being blockled, the jacked wheel will turn 60 mph..and if damaged bearing noise is audible. I DO NOT BRAKE HARD, let it coast to stop. Down the wheel, and I do same test on other wheel. Noise difference between normal and failed bearing is very noticeable...bearing rarely happen to fail both at same time.
Bearing change is rather easy. Come back for details if needed.

change the pass side wheel bearing hub ASSM and be done with it.the montana venture silloette are known for bearing going out.if the tranny was doing the noise there would be fluid running out of the trans...........

change the pass side wheel bearing hub ASSM and be done with it.the montana venture silloette are known for bearing going out.if the tranny was doing the noise there would be fluid running out of the trans...........

If there is anyone who has replaced the wheel bearing could you run through the basics for me. And could you tell me how much to expect to pay for the bearing?
Thanks SSgt David White US Marine Corps

check this thread: lot of details are discussed..it has not changed over the years .
http://www.automotiveforums.com/vbulletin/showthread.php?t=648414
www.avigex.ca/xport/hubremove.jpg
this from autozone:
www.avigex.ca/xport/hubremoval.pdf
After market price is 'round 170$(cdn) and round 150US has been reported.