I have a new noise, which I've started noticing throughout the summer...

When travelling in 4th/5th/6th gear, I can hear a low-pitched rumble alongside the engine/exhaust note, particularly between 50-70mph.
It's not engine related as the pitch of the rumble corresponds with road speed, regardless of gear.
It's also unaffected by acceleration and is noticeable whilst cruising at a constant speed on smooth tarmac roads.

I don't think it's tyre related, as it's much too fast to correspond with wheel rotation (I've just had my wheels rebalanced, although new front tyres are due soon).
I've also had the handbrake refurbished at the same time- my first thought was that it was dragging again, but it's been readjusted and made no difference

An educated guess would suggest the propshaft, but what else could it be?
I've got no diff whine (except perhaps a little resonance at the front at 43mph, which it's always had in the 5 years I've owned it) and it hasn't really got any worse over the few thousand miles I've done over the summer.

Do propshafts go out of balance?
Or has a bearing or CV joint started to fail?

Ideas? "We're in danger, we've got to get out."
"What are you talking about?"
"I've been called a ponce."

Do propshafts go out of balance?
Not really

Or has a bearing or CV joint started to fail? ?
possible wheel bearing
In my experience CV joints more noticeable at low speeds and when turning.

However I would swap tyres front to back to see if that makes any difference. Tyres can make all sorts of noises especially when worn. Jules

Tyres will be the next thing I'll try then... The fronts (Michelin Latitudes) have worn down to 2mm over two years, whilst the rears have both been changed within the last year or so (I'm forever eating through tyres- potholes and bits of flint giving me flats here in Norfolk).

Don't propshafts have balancing weights?
It's not something I know a great deal about as my previous motors have all been FWD.

As for CV joints, I seem to recall they clatter under high torque when pulling away- it's certainly not that.

I should also have mentioned my Freelie is a 2007 Manual with 230,000 miles on it. "We're in danger, we've got to get out."
"What are you talking about?"
"I've been called a ponce."

If the prop shaft u-joint wears out, that will cause it to flop around a bit resulting in a rumbling noise. IIRC I noticed it at lower speeds but I usually have the stereo on by the time I get to the highway.

Lord Rich Tea Biscuit wrote:

Don't propshafts have balancing weights?

Both the above are possibilities then...

Whilst there is some driveline 'slop' noticeable when changing up gears, I'm not getting any other peculiar noises at this stage- no clunking like one would expect with a front axle CV joint. "We're in danger, we've got to get out."
"What are you talking about?"
"I've been called a ponce."

jules wrote:

Do propshafts go out of balance?
Not really

Or has a bearing or CV joint started to fail? ?
possible wheel bearing
In my experience CV joints more noticeable at low speeds and when turning.

However I would swap tyres front to back to see if that makes any difference. Tyres can make all sorts of noises especially when worn.

I can attest that it doesn't like worn tires at all.

New front tyres on and the slight rumble is still there. Seems to resonate most at 50mph and most noticeable in 5th gear (musically seems to be a perfect fifth in relation to the engine note) but hasn't got any worse since the summer and I've done a few thousand since then! "We're in danger, we've got to get out."
"What are you talking about?"
"I've been called a ponce."