Replaced inner/outer ball joints, tie rod ends, strut mounts, and front wheel bearings 5k miles ago.

When in 1st/R gear, while letting out clutch from a stop, there's a clunking. On the freeway above 70mph, it warbles.

Do I have a messed up axle?

There's a guy on craigslist selling a (chinese) ODM brand axle for $20 that he has had leftover from an old MINI.

Is it okay to only replace one side at a time? Can it hurt anything? At least, wouldn't it help me troubleshoot the noise?

Thanks in advance!

 

bump, still there. any ideas?

 

With all you have replaced the axle seems to be the culprit. I'd replaced the right side a couple of times and would tell you find the most expensive one (factory if you can swing it) that you can afford. I'd done the cheap replacement and that didn't fair too well (maybe a year). The right axle has a bearing mid-shaft that tends to be the issue as this is the longer of the 2 axles. Yes, it's fine to only do one.
If you're at all handy you can do this yourself. I used to drop the lower engine mount and that gives you access to the 2 bolts that hold the bearing guide, unbolt the lower ball joint bolts, remove the bearing and you have access to just slide the old one out (it takes some effort.)