weird groaning noise is back!

hello again, I have a 2003 RR autobiography, 100,000 miles; I had this problem a year or two ago and it eventually went away. Basically, I drive along, around 35-55 mph and intermittently, I hear an annoying groan from around the underneath of the offside passenger seat. It doesn't last long...merely 0.5 seconds then comes back again maybe a few seconds or minutes later. The noise is always in little bursts. I had someone change the rear diff oil which was pretty clean, but changed anyway....noise still there. It just comes and goes and is most noticeable when pottering along without foot hard down, but I think the car is under load when I hear the noise. It can best be described as a low groan.....or like going over mild rumble strips, but it is short lived as it comes in bursts. Its not buffeting from wind etc....def a kind of groan or booming noise, a bit like the base unit was up loud and it was vibrating really badly....it makes no difference if I switch to sport mode....or automatic. PLEASE help if you can, regards Simon

Front diff ?

Has yours had the new type one fitted as there was a recall on them ?

Wheel bearing ?

Thanks for the comments. Sorry I should have said, its coming from under the rear passenger seat, offside ie behind me the driver. Considered the wheel bearings but its so "on and off" a garage said wheel bearings issues don't sound the same. They were equally confused but not range rover experts.

also, I'm not sure about a recall. I've had the car for about 3 years...not sure what to look out for or what to do next with the recall question.

Is yours a diesel or petrol ?

Take the batteries out of the wifes vibrator.

its petrol with LPG

wammers said:

Take the batteries out of the wifes vibrator.

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Or as I did, DIVORCE her

Beat me to it! I was going to suggest leaving the wife behind.

The rear bushes have been known to wear with alarming regularity.

Also the rear propshaft bearing can wear...this is hidden above the fuel tank unfortunately.

Thanks everyone, divorce isn't an option, its too expensive.

Thanks also Saint V8, as I thought from the beginning that it sounded like it was around the fuel tank area, and I wondered if the fuel tank had come lose of its bolts or something. Even when it isn't making the actual groan noise, from 40mph up, the rear of the car does sound as if there is too much resonance ....as if the fuel tank is acting a bit like a poor speaker....and its a bit like wanting your ears to pop at altitude. Unexplainable subtle booming noise. Rear prop shaft bearing could make some real sense. On a drive last night, it got really bad going up a moderate incline at 50pmh. Let the gas off and it pretty much went away until gasing it again.

Hmmmmmm.....

Thae fact it happened on an incline around the warning speed of 50mph on light throttle leads me to suspect it could be the Torque Converter Lock Up Clutch....

This produces a rumbling feeling but not so common is a groaning/rumbling sound, but that is not to say it can't....

Have you had the Gearbox oil and filter changed recently?? if not, why not? D), but if you did, what was the fluid like and if not, do it and check the quality of the fluid.

It could still be the propshaft bearing as when torque is applied to the shaft it will try to move laterally putting more pressure on the bearing to oneside causing a groan...then when off throttle the propshaft returns to running centrally in the bearing housing and ceases groaning.

Gearbox Oil change first if you havn't done so already.

Saint.V8 said:

Hmmmmmm.....

Thae fact it happened on an incline around the warning speed of 50mph on light throttle leads me to suspect it could be the Torque Converter Lock Up Clutch....

This produces a rumbling feeling but not so common is a groaning/rumbling sound, but that is not to say it can't....

Have you had the Gearbox oil and filter changed recently?? if not, why not? D), but if you did, what was the fluid like and if not, do it and check the quality of the fluid.

It could still be the propshaft bearing as when torque is applied to the shaft it will try to move laterally putting more pressure on the bearing to oneside causing a groan...then when off throttle the propshaft returns to running centrally in the bearing housing and ceases groaning.

Gearbox Oil change first if you havn't done so already.

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If it is that he needs to sort it PDQ before the debris from the torque converter causes the gear box to slip the mortal coil.

Nobody seems to have mentioned it, probably with good reason, but has anyone thought of the fuel pump ?

Thanks again Saint V8 and others.

Im going to have someone do the gearbox oil and filters etc, but can I ask SaintV8 about the groaning being so intermittent. It isn't just groaning all the time....I can accelerate up an average hill at 40-50 it groans and maybe 0.5 secs later it stops...then groans again...so it comes and goes. Its pretty difficult to listen to it because it can be so short lived. This is why when taking my foot off the pedal it is difficult to know whether its reactive or coincidence....could it still be the propshaft bearing with it being intermittent....would a failed bearing perhaps not make more of a constant noise....rather than somewhat more random? So I could be doing 50mph up hill, it groans, I maintain my speed and throttle, but then the groan totally stops, then could come back 2-3 seconds later.....
I am just trying to give you a feel for whats happening.

Thanks again in advance

smartone said:

Thanks again Saint V8 and others.

Im going to have someone do the gearbox oil and filters etc, but can I ask SaintV8 about the groaning being so intermittent. It isn't just groaning all the time....I can accelerate up an average hill at 40-50 it groans and maybe 0.5 secs later it stops...then groans again...so it comes and goes. Its pretty difficult to listen to it because it can be so short lived. This is why when taking my foot off the pedal it is difficult to know whether its reactive or coincidence....could it still be the propshaft bearing with it being intermittent....would a failed bearing perhaps not make more of a constant noise....rather than somewhat more random? So I could be doing 50mph up hill, it groans, I maintain my speed and throttle, but then the groan totally stops, then could come back 2-3 seconds later.....
I am just trying to give you a feel for whats happening.

Thanks again in advance

Click to expand...

This is what makes me think it could be your Lock Up Clutch in the Torque Converter.....

The Gearbox ECU modulates the Lock Up Clutch pressure to try and minimise TQ slippage hence why the tell-tale signs are a rumbling/juddering sensation as the LUC is rapidly applied then retracted, then applied again - like going over a subtle cattle grid....

As the LUC wears due to this modulation, the rumbling/juddering gets more and more evident until it just gives up....

this is why taking a gander at the gearbox fluid is helpful as colour and composition can give clues as to if there is a lot of friction material debris in it or not indicating LUC excessive wear.

What causes the LUC to modulate in the V8's ZF box is failure of an axial bearing allowing two Clutch packs to move axially along their shaft....this wears out the O ring inbetween two clutch packs...this causes the A Clutch to slip due to reduced hydraulic pressure leaking across the failed O ring...the LUC is then called into action more than it was designed to to limit the slippage of the A Clutch...this prematurely wears the LUC friction material causing failure.

Get the oil changed to assess its condition.

Probably silly but similar to the noise I had from slight seize on calliper.

Saint V.8 becomes Saint again.

Just had my torque converter removed, sent for refurbishment in Sussex, returned within 2 hours with replacement lock up clutch etc.....refitted into the car and it drives like a dream (for the 15 minute drive to the office). Long trip ahead so will come back in 10 days and report. The garage took it for a 30 min drive and reported no problems and they could hear the groan beforehand. Fingers crossed but the torque converter and lock up clutch seem to have been the problem. The confusion for me, was that the noise was in the rear, but yet the transmission is obviously at the front. Thanks again for all your help.

Glad to hear it is sorted...fingers crossed.

Could I be coarse and ask where you had your work done and the approx cost??

Hi Fellas.
Having read the thread i am very tempted to think that the same problem as mine. Almost perfect description of symptoms...
I too would like to know how much for a bench mark figure.
Cheers, Nick