replacing the bearings should be a relatively easy job (for the mechanicly inclined)
each wheel has an inner and outer bearing and a grease seal. if the races (where the bearing rides on) are good, just clean out the old grease, pack the bearings and replace the seal. reinstall with new hardware. the races need to be pressed in if bad.
$320 doesnt seem outrageous if that includes new parts.
good time to look at the brakes too.

 

I have probably the same sound... There's a write up that someone did in the write up section on how to replace the original thrust bushing with a needle bearing and a new thrust bushing. Anyway... I haven't gotten a chance to get the spindles off and do the job... it just seems like it'll take forever... plus, I need to find someplace that has a hydraulic press to make it easier.

 

REgarding the bearings - "needle bearings" are just small roller bearings. None of the wheel bearings are 'properly' called 'the needle bearing.' None of the wheel bearings are needle bearings, but they are all roller bearings. (The other type is ball bearings) Needle bearings are typically straight (and each roller is about the size of a toothpick) and roller bearings are bigger, typically tapered but not necessarily, and come in all sizes.

Properly identified, the spindle/hub has an "inner bearing" and an "outer bearing." They can be called wheel bearings or spindle bearings - both names are correct. Inner wheel bearing/outer wheel bearing, inner spindle bearing/outer spindle bearing - same same.
The inside bearing races slip onto the spindle and the outside races press into the hub.

The bushing discussed above (and replacement with bearing mod) is something else entirely. Where the drive axle goes through the backside of the spindle, it goes through a simple brass bushing, and there's a dust cover over that. This can be replaced with a bearing if you wish, but it is not necessary - the bushing carries no real load, it just serves to keep the axle centered in the spindle. I can wear out over the years, but generally lasts a long long time.

Here's a diagram of the bearings and the bushing.

 

Thanks for the clarification!!