Ford / Volvo M66 trans output - drive shaft grumbling

So, I'm going back in time for all the info on this.  2-3 years ago I did a 100K service on the my Volvo C30, timing belt, water pump, tensioner etc.  While doing that I noticed that a couple of CV boots were torn.  Rather than just replace the boots I figured I get both axles rebuilt so they'd be good for another 100K miles.  Big mistake.  I wish I'd never done that.  I took the axles to Detroit Axle which is THE place to go inthe Metro Detroit area.  Well I put them back in and the right hand CV joint exploded within 1/4 of a mile on the first test drive.  Bugger.  I took it back, much profuse appology.  They said they'd turn it around the same day, or if I waited until the next day they'd get their longest serving best guy to do it. So I waited.  Got the axle back, poped it in and happily set off.  This time it made it al of perhaps 15 miles before exploding.  berkeley this I'm never going back to Detroit Axle no matter what.  So I ordered a replacement from Rock Auto and have been driving it ever since.  Well this last winter it started grumbling.  I thought I'd wait until spring and rebuild it over the summer.  But then I got downsized and had to turn in our company cars so the Volvo is now our primary DD rather than my winter car.

So yesterday I go to do and oil change and investigate while under there.  I had a poke around and wiggled things expecting to find free play in one of the CV joints, but it's not that.  The only free play is at the inner end where the right hand shaft (the problem one) goes into the trans.  There there is at least 5-10 degrees free play rotation.  I've no idea if it's just the splines wearing, the output bearing, the mating internal splines in the trans or a combination of all three.  Not sure what to do right now.  Thoughts?

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Wow, it's awesome righting things down to share this morning.  My brain has suddenly engaged gear and I realize it's most likely the splines on the Rock Auto Chinesium drive shaft and hopefully not anything else.  So, assuming it is the Chinesium splines, whats the chance that replacement and a fluid change will fix it?  I ignored it all winter as I planned on having the car off the road for six months so it's probably got 5K miles or more with the issue.  Could I have damaged the internal splines as a result?

TIA

So this is the OEM shaft that I've stored in the box the R.A. Chinesium part came in.  I pulled it out to have a look.  Believe it or not I've never rebuilt CV joints (or Lobro joints asI grew up calling them) before.  My old cars (Imps) had UJ's not CV's inthe drive shafts and everything else has either been live axle or even on my high mileage and race cars I've never had an issue with one in over 30 years. 

Once the boots are removed how easily should you be able to pull the joint apart?  The inner one is still together in these pics as there is significant resistance to them coming apart. I assumed once not restrained they would pop apart easily like the outer.

Inner joint that's reluctant to come apart.

Bookmarking this so I can reply once I get home.  The connection here at work suuuucks.

Okay, none of the photos showed up at work OR here at home.

Damn, I have really bad luck linking pics from my Google Photos account so I've DL'd to my hard drive and uploading direct to the site instead.

When we still had my wife’s c30, I did the passenger cv after the boot let go and just bought a new axle from autozone for it. 

By by the time the cv replacement was absolutely necessary it sounded like it could come apart at any second.  Started with just a feeling like the trans slipping under power and progressively got worse. 

Your grumbling sound seems to me like a wheel bearing

Hang head in shame and revokes man card.  Actually that's not true, revoke car card.  Anyone of any gender should have realized it was the wheel bearing.  I was just focused on the wrong thing because of the prior issues with the drive shafts.  Rock Auto part ordered and will fit along with rebuilding the front calipers this coming weekend.