Mysterious knocking sound, what could it be?

Had a mysterious knocking sound coming from what seems to be the left side, which we orginially thought was the exhaust vibrating of the chasis as it only happens at high revs & when driving slower, doesnt happen on the moterway.

But having been underneath it doesnt seem thats possible. Were now wondering if it could be the drive shaft?

Anyone have any ideas?
& any ideas how much a drive shaft is to replace?

thank you !!

Any additional information on where the sound is coming from ???

Would also need to know the configuration of your defender (90/110/CSW)

At a guess, mine rattles at idling revs due to poorly fitted sliding windows in the rear,

So maybe body fitting has come loose ?

Just a pointer, a Hayes manual can set you in the right area if you know roughly where the noise is coming from,

Quite hard to guess with the information presented,

Additionally any local members on the site might be able to help out if your lucky

Its a 90, it sounds like its underneath but quite close to the left outside if that makes sense thats why we thought exhaust it seems like metal vibrating of metal.

I dont have sliding windows in back but will def give the body a check over

Is a hayes manual different from the 1 that comes with the car (excuse me if i sound rediculously stupid !! )

Trouble is, not patronising but, you don't 'know' what the sounds are .. and a Defender is a metal box with lots of inter-connected metal tubes .. which resonate and transfer sound very readily.

So much depends on the type of knock or vibration .. as it's when driving slowly, get someone with a bit of an idea to stand outside as you drive by. Could be as simple as a stone in the disc stoneguard, to an exhaust clamp, to a bush .. to almost anything!

Whereabouts are you? Someone off LZ might be able to help diagnose ...

Don't worry I'm very clueless atm I'll accept that !

My dad pretty good with cars so were going to have another look tomorrow & if not we've got a friend who has a garage who knows a landie specialist so going to take it over to him.

I'm Middlesbrough, North Yorks

Paul D said:

Trouble is, not patronising but, you don't 'know' what the sounds are .. and a Defender is a metal box with lots of inter-connected metal tubes .. which resonate and transfer sound very readily.

So much depends on the type of knock or vibration .. as it's when driving slowly, get someone with a bit of an idea to stand outside as you drive by. Could be as simple as a stone in the disc stoneguard, to an exhaust clamp, to a bush .. to almost anything!

Whereabouts are you? Someone off LZ might be able to help diagnose ...

Click to expand...

Told you Kassie,


A Hayes manual is different the to one provided by LR,

A Hayes manual is a good purchase with a Land Rover Defender as much work can be done with simple tools and some elbow grease,

Does your 90 have any sound proofing (thick carpets in foot wells and rear) ?

Like Paul said, its a big metal box (also known as a cattle shed on wheels)

Its not like any car you've probably owned yet, there's little or no sound proofing and the ride is questionable for the passenger,

Work out what normal running sounds like with it so if anything changes while running you can quickly isolate is anything wrong,

I strongly recommend a new stereo and explore new speakers, drowns out the noise on motorways

PS, it's Haynes manual ..

My son's in Middlesborough, at Teesside Uni studying for Game Design and 3d Animation degree .. not that he'll be any use .. and we'll be up there in a fortnight. If it's still knocking I'll maybe have a listen ..

I have put in rubber mat on the floor & bench seats in the back but not finished it just yet

I prefer tank to cattle shed, but i suppose its a fair description

Think I'll invest in 1 of those then, thanks

A stereo at all would be a good start old or new!

Paul that would be great! I'll let you know how we get on

"Cattle shed" If i put cattle in ma Tratter where would my pig sit He won't be a happy pig

grimmer said:

"cattle shed" If i put cattle in ma tratter where would my pig sit He won't be a happy pig:d

Click to expand...

passenger seat

Jonnyb1990 said:

passenger seat

Click to expand...

That's where Mrs Grimmer sits, ma pig goes in the back with the dogs normally, not sure the dogs would be too happy either trying to squeeze cattle in anorlound:

Kassieg said:

Had a mysterious knocking sound coming from what seems to be the left side, which we orginially thought was the exhaust vibrating of the chasis as it only happens at high revs & when driving slower, doesnt happen on the moterway.

But having been underneath it doesnt seem thats possible. Were now wondering if it could be the drive shaft?

Anyone have any ideas?
& any ideas how much a drive shaft is to replace?

thank you !!

Click to expand...

Morning if you say its near the exhaust on the left hand side have you checked the intercooler to turbo pipe.

Standing in front on your defender open bonnet. At the right of your radiator is the intercooler (looks like a smaller radiator). There are 2hoses one at the top and one at the bottom leading out of the intercooler.

Looking at the bottom hose follow it up and there should be a metal pipe shortly before a 90* hose to the turbo. The metal pipe should be fixed to the wing with a clamp and rubber sleeve. Picture attached

I had the same rattle and it turned out to be this pipe, the clamp had rotted away and the pipe was banging on the wing...

have a buthchers you never know?