STILL have a drone/vibration driving me insane

[Sea Aych]

car: M50 swap, stock Getrag 260, driveshaft, 4.10 diff.

I just had my driveshaft rebuilt (new u-joints, csb, balance, etc.), thinking it would solve my problem, but it hasn't...

I'm getting a LOUD droning noise above 30mph, getting loudest at around 45mph. It sort of sounds like it's coming from the back, but it's hard to tell since it resonates through the whole cabin. There is a slight vibration that goes along with it, but it's smallish compared to the noise.
It's entirely speed dependent, as it continues if i pop the clutch in, or go the same speed but in a different gear (different revs)

My headers aren't touching the subframe or the sway bar, i'm on stock trans mounts, guibo is looking fresh, and the driveshaft (as mentioned) is just rebuilt professionally.
I'm at the end of my rope and have been battling this extreme drone for almost six months now. Any more ideas?

Any other ideas?

[Varinn]

Wheel bearings?

[Tim-sutherland]

Wheel bearings?

Sounds about right to me. I could think straight again after mine were replaced.

[packratbimmer]

Can you alter the drone by accelerating/decelerating? If your rear subframe bushings are completely shot, the new u-joint in the back will be on a bind. Jack the car up from the center (diff.) enough to see if the rear subframe bushings are sloppy.

[Sea Aych]

Sounds about right to me. I could think straight again after mine were replaced.

Doesn't seem like it as i couldn't make it change tone with turns. then again it's a little hard to turn sharply enough in town at 70kph without attracting a ton of attention

Do they cause a droning noise + slight seat vibration to match when they're going?
Closest way i could describe the sound would be a BRRRRR with a fast faint bumbumbum going on underneath.

Can you alter the drone by accelerating/decelerating? If your rear subframe bushings are completely shot, the new u-joint in the back will be on a bind. Jack the car up from the center (diff.) enough to see if the rear subframe bushings are sloppy.

Bushings look decent, definitely no play

[Varinn]

If nothing else they are an easy thing to check, you can lift the car one corner at a time and do a top/bottom and side to side check by by grabbing the wheek and giving it a bit of force in each direction (push/pull). Fronts you can also check condition by giving them a spin by hand, they should be very smooth with a slight resistance and spin down after a few rotations. If they spin easily 10+ times they are dry and have more clearance inside from wear.

[Sea Aych]

If nothing else they are an easy thing to check, you can lift the car one corner at a time and do a top/bottom and side to side check by by grabbing the wheek and giving it a bit of force in each direction (push/pull). Fronts you can also check condition by giving them a spin by hand, they should be very smooth with a slight resistance and spin down after a few rotations. If they spin easily 10+ times they are dry and have more clearance inside from wear.

No play in the rears, seems to be fairly smooth too.
I can hear a faint whine from the rear right when driving, but it's hard to tell with the level of drone

[Sea Aych]

update - switched out my trans mounts, re-preloaded the csb, which helped a little, but oddly enough it now sounds like the noise is coming from right between my ass and the firewall....
lost. CVs are fairly clunky when setting off, but there's no popping noises. could that still cause a rumbly vibration?

[Fixedwheelnut]

If you have a thumping as well how about tyres out of shape, jack it up on stands and drive it up to speed and look at the tyres.

[Sea Aych]

If you have a thumping as well how about tyres out of shape, jack it up on stands and drive it up to speed and look at the tyres.

Well I think that did it!
It was hard to tell until I had it running on stands with someone else at the wheel so I could look under.

The right axle isn't rotating on its own centre axis..... Hence the vibration. Speed up and it's a blur compared to the drivers side which is stable and spinning nicely.

CV joint is done. New axle time!