Severe wobble/vibration on LH cv half-shaft

Its a Jetta tdi 2006 with 250k miles. It has a vibration problem with drive train that got progressively worse. The tire service center has got all problems squared away that could cause vibrations, its not a tire or wheel problem. The front end was also aligned, this had no effect on vibration. I jacked the car up off the ground and ran it. The lh cv half shaft has a very pronounced wobble as it turns. This of couse causes a severe back&forth movement of the whole engine. I figured it was a worn out cv joint. (I did note the boot on the lh front strut is torn, but the car front only bounces once when you push down on it). The lh front wheel bearing is fine, turns completely silent. Well i replaced both cv half shafts....but no change in wobble/ vibration. A worn srut would not cause such a wobble would it? I have taken it to two car service centers they dont know either. I am debating whether to throw another 80.00 for new lh front strut (again doing the job myself) at it, plus another alignment. What is fix for this? If its the transaxle itself i am putting big bucks down a rathole as it would be way too much to replace tranny!

Well Chaxles are junk, if that is what you have been using. You can easily rebuild (reboot) the original OEM axles OR they are available in the aftermarket for a reasonable price (GKN/Lobro... not the Chinese junk).

However, even a new Chaxle is generally OK for a few months at least. So you may have something else going on. Is the driveline off center for some reason? There is a left to right adjustment, shown by the elongated holes in the engine and trans mounts, but normally would not get THAT far out on its own.

But I have seen brand new Chaxles bad, too, just not very often.

Can i safely rule out the dsg transaxle itself as the cause? I even took out lh front wheel and half-shaft, ran engine slow and giving some throttle. Put a little piece of cardboard up to the output shaft from transaxle, and it rotates perfectly concentric it seems, and with it shut
down, there isnt a bit of slop in it.
I am wondering now if the bad lh half shaft wobble i am seeing could be simply because with the struts extended fully, it being jacked up on both sides off the ground- this abnormal extension is making too much of an angle at the outer/rotor u-joint? I know if it is beyond a certain
In number of degrees bend, then it is going to wobble.

I bought the new (not reman) cv half shafts at OReilly Auto parts. Cant remember brand name now, though.
Now i am wondering if the last/ second auto repair place could be right. They say the tires are becoming cupped, and all 4 struts need replacing. This is their diagnosis after i told them about the lh. Driveshaft---the new one also---wobbling . The front end only bounces once when pushed on, and there is no tendency of front of car to dip, and no excessive body roll in turns at all. But still, i dont think it has ever had struts replaced yet after 255k miles! So i am going to get two new front struts for $240.00 and replace them both myself.

Okay let's back up up a bit.

What type of vibration is this, as in when exactly does it happen?

Is it rhythmic with rolling speed?

Worse under acceleration?

Any changes better or worse with various road surfaces?

You are correct that the shaft is extended with the suspension unloaded, not really the best way to check for this sort of thing. Plus, with no weight, there will be no load.

You can balance a tire/wheel combo all day long that is out of round. It will still be out of round. Wheels bend easily on these cars, for whatever reason. I've never bent one, but it is an almost weekly occurrence here that some VAG product comes in here with a bent wheel. We've already had three this week, and it is only Wednesday.

Crappy tires will scallop the inside edges on that car. Not rotating the tires as specified will make that worse. While the struts could certainly stand a refresh after nearly 1/4 million miles, it is rare to see the A5 cars' struts/shocks downright "blow" like you see on many other cars to the point that the wheel is violently bouncing all over the place in the wheel arch driving down the road. It isn't a Cobalt.

You also will benefit from the updated control arms, as those had issues with creaks in the cold over bumps (there is a TSB for this), and the rear compliance bushings in the arms are certainly fatigued at this point. But they generally don't completely break apart like the A4 cars do so commonly.

Like i said previously i could not dtect cupping after carefully cheching tires with a depth gauge. I am lately hearing a loud metallic knock sometimes when i hit a big bump or pothole. I decided that if the rapid whir-whir or scrape scape sound isnt the tires themselves then my earlier idea that the the lh driveshaft is wobbling is what causing the constant scrape-scrape varying with rpm.
Since i dont have a dynamometer, what was needed was some video telemetry showing the lh driveaxle while driving. So i velcro'ed my new odvrm action cam to the front insde of wheel well. Drove it few miles, recording 4k video. It also had a picure on my cellphone, so i could watch driveshaft as we were driving via the cameras' wifi signal. The video shows the outer cv joint does indeed have a pronounced wobble! This in spite of just having installed a new driveshaft as well as a new hub and bearing assy. How can this be? Clearly its a suspension problem...and the inside of the left front tread is already worn down to 4mm when outside is still 5 mm! Ideas? This is causing such a bad vibration, in the steering wheel, too....that nobody will want to buy the car! Thakns all.

Goodyear auto re-aligned all four wheels after i replaced a number of suspension components (mentioned in earlier posts). I asked them to check tires for any cupping and they said they are not cupped. Discount Tire telling me the vibrations were from cupped tires was BS as I thought! I made a video from within the car this time, to record the "knock-knock" noise. If one listens carefully it can be heard. Its not a metallic knock at all. Its obviously some rotating part that is not rotating true/balanced. Its not a rotor, as the brakes are perfect....no pulsations at all.
Here is the facebook link:
https://m.facebook.com/story.php?story_fbid=1936473079746247&id=100001507225680

Dont think it could be a loose steering rack....this would make a mettalic rattle...but a steering rack does not rotate. This noise is made by something which is rotating.