Pulsating sound between 45 and 52

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Newbieowner

Newbieowner

New Member
Posts
4
Location
Norfolk
Hi all, I'm a new defender owner finally after wanting one forever, I've just acquired my fathers defender 90, he had it from new (1992) so know it's never been trashed and has full service history, I have a strange throbbing, pulsating sound between 45 & 52 mph which just seemed to appear, I've had the gearbox rebuilt after it decided to die taking the transfer box with it, I'm sure the sound wasn't there before hand but it is now, I'm sure it's in the drive train somewhere, I've rebuilt the rear diff, new ujs front and back, front output bearing on transfer box, wheel bearings are all done but the sound is still there, all the things I have done have altered the noise but not cured it, I'm at a loss now, any ideas? Handbrake drum?
 
Try all the obvious things to locate - remove one prop shaft and test run, see if it happens on overrun (freewheel down a hill). Could even be one of the tyres - get them balanced/checked.
 
I've done the bearings, was my first port of call, the wheels were freshly balanced only a month ago, noise was there before and after balancing, will try the prop shaft trick when I can, I'm in Norfolk so there are no hills in these parts to check the free wheel trick.... Thanks for your ideas
 
They're maxxis 751 bravo radial 245/70 the sound was there before I swapped the wheels from the old steelies and nobblies
 
Newbieowner said:
Hi all, I'm a new defender owner finally after wanting one forever, I've just acquired my fathers defender 90, he had it from new (1992) so know it's never been trashed and has full service history, I have a strange throbbing, pulsating sound between 45 & 52 mph which just seemed to appear, I've had the gearbox rebuilt after it decided to die taking the transfer box with it, I'm sure the sound wasn't there before hand but it is now, I'm sure it's in the drive train somewhere, I've rebuilt the rear diff, new ujs front and back, front output bearing on transfer box, wheel bearings are all done but the sound is still there, all the things I have done have altered the noise but not cured it, I'm at a loss now, any ideas? Handbrake drum?
Click to expand...
Is it just body noise?
Sometimes quite a small vibration, maybe from tyres rotating at a certain speed, can be amplified by the panels. Is there any deadening mat in your bonnet, doors etc?
 
Seems to me the one thing you haven't listed is halfshafts/CVs, and symptom sounds like halfshaft wobble. Fairly easy to pull, but greasy job.
 
Don't think it's body noise, I can feel the pulsating sound through my feet and definitely sounds like it's coming from the rear that's why my talented friend and I rebuilt the rear diff and did the rear ujs first this did help the noise a little, I did think half shafts after reading something on hear I think, I'm trying to get the old beast as good as I can as do quite a few miles a week, happy to replace the half shafts just for the hell of it as I presume they are original, any ideas of cheap good ones if there is such a thing
 
Could be as simple as halfshaft seal.
Original is pretty solid, you can get a used axle on ebay for not much with a half ton of misc spares. Inspect before buying, obv.
 
Have a good look at the paint finish on you your prop shafts, if you can see a small (1 inch) patch of missing paint then you may have thrown a balance weight which is causing the vibration. If you have, try and fabricate one to the size of the paint patch out of 1.5mm (ish) thick steel and weld it to the spot.
 
Newbieowner said:
Hi all, I'm a new defender owner finally after wanting one forever, I've just acquired my fathers defender 90, he had it from new (1992) so know it's never been trashed and has full service history, I have a strange throbbing, pulsating sound between 45 & 52 mph which just seemed to appear, I've had the gearbox rebuilt after it decided to die taking the transfer box with it, I'm sure the sound wasn't there before hand but it is now, I'm sure it's in the drive train somewhere, I've rebuilt the rear diff, new ujs front and back, front output bearing on transfer box, wheel bearings are all done but the sound is still there, all the things I have done have altered the noise but not cured it, I'm at a loss now, any ideas? Handbrake drum?
Click to expand...
Can i first ask what the rear diff symptoms were to make a rebuild necessary? the sound you describe i would have said ujs, Have you replaced all 4, front & rear props and packed them with grease?
 
I was going to suggest body vibration too. Get someone to sit in the back and put their hand on each panel in turn to see if it goes away. Sounds daft, but it works on mine, and knowing what it is I just got used to it!
Disclaimer: If it's a hardtop with no rear seats and you get pulled over for carrying a loose passenger in the back of a van, it ain't my fault! :)
 
This may be out of the box thinking but was a new clutch fitted when the gearbox was repaired?
Was a new dual mas flywheel fitted?
A Dual Mass Flywheel is basically two components (the primary & secondary mass) linked together by a damping mechanism within the secondary mass and located by the central carrier bearing. The damping mechanism is there to absorb the torque loads of the crankshaft and to help deliver a smooth transfer to the road wheels via the clutch.

As time passes and the vehicle's mileage increases the damping mechanism softens and weakens. As the mileage increases the damping mechanism becomes weaker to the point where the movement between the primary and secondary masses becomes excessive. When this happens the flywheel tends to vibrate or rattle when driving.
 
Mine gives me a lot of vibration at around 50 mph when the propshaft joints are getting loose. You don't necessarily feel it straight away from the transmission, but it makes other parts of the car, such as the body panels more rattly.
 
Tim4x4 said:
This may be out of the box thinking but was a new clutch fitted when the gearbox was repaired?
Was a new dual mas flywheel fitted?
A Dual Mass Flywheel is basically two components (the primary & secondary mass) linked together by a damping mechanism within the secondary mass and located by the central carrier bearing. The damping mechanism is there to absorb the torque loads of the crankshaft and to help deliver a smooth transfer to the road wheels via the clutch.

As time passes and the vehicle's mileage increases the damping mechanism softens and weakens. As the mileage increases the damping mechanism becomes weaker to the point where the movement between the primary and secondary masses becomes excessive. When this happens the flywheel tends to vibrate or rattle when driving.
Click to expand...

:confused: He says his motor is 1992 model! Dont think they have dual mass flywheel?
 
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