I've got a rumbly noise, which sounds very much like it's from the passenger side when I'm sitting on that side and very much like it's coming from the driver's side when I'm sitting on that side. It goes quieter when I steer left, kind of making me think it's on the driver's side (right).

What about the bearings in the end of the axles that support the distal end of the half-shaft? I don't see them advertised as a replacement part anywhere so I assume they live a gentle and blameless life, would that be right?

When you turn left, the weight of the car is shifted towards the right, so it makes the LH wheel lighter and the RH wheel heavier.
If the rumbling noise goes quieter on a LH corner, it will be because some of the weight is taken off the LH wheel bearing.
You can't really tell unless you take the whole hub off and spin it in your hand, imho.

I agree, I haven’t had a bad hub on my LR’s yet, but on a Dakota I used to have with a bad front wheel bearing I couldn’t tell which one it was until pulling it apart. I would think that if one bearing is on its way out, it’s mate won’t be far behind though.

you can sometimes tell by simply jacking it and spinning each wheel and seeing how it sounds. Especially if you compare side to side you might notice one feels or sounds rougher. however due to drag on the brakes and depending on how worn the bearing is etc its not always foolproof.

I dont think there are any bearings in the outer end of the front axle case? there is a plain section of shaft that runs in the oil seal, and otherwise its supported by the CV joint/wheel bearing itself.

This might be the perfect occasion to buy one of those 'mechanics stethoscopes'?? If you did as suggested above, and jacked the wheels, then you could go from one to the other seeing if you could hear a difference? Obviously you can't put it on a spinning wheel...... (!) but you would probably pick something up from the hub or knuckle - somewhere you could get the probe into.

I say this as I've bought one years ago (not expensive) but not found the opportunity to use it yet.

There is definitely a bearing in the older Series axles, as I remember having to source one for a Series IIA that had more water than oil in the front axle, and of course the bearing was completely rusted as a result. Not sure the same setup is on the P38, and the parts list doesn't show anything obvious either. I don't recall seeing one in the D2 when we had the driveshafts out to do the balljoints.

it dose sound like a wheel bearing , fun to replace ,not.

Aragorn wrote:

you can sometimes tell by simply jacking it and spinning each wheel and seeing how it sounds. Especially if you compare side to side you might notice one feels or sounds rougher. however due to drag on the brakes and depending on how worn the bearing is etc its not always foolproof.

I dont think there are any bearings in the outer end of the front axle case? there is a plain section of shaft that runs in the oil seal, and otherwise its supported by the CV joint/wheel bearing itself.

Assuming of course you have removed the prop shafts or lift a complete axle at a time. The VCU might have something to say about “spinning each wheel”! :)