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Clunk then a clunk continuously under load.

Looking more at this I think that’s old damage as the bearing is in very good shape.
 
I doubt it will be caused by bearing wear.

It started, like the Universe, with a bang - something gave way, but what?

The forces involved are such that it may not be obvious when looking or just poking about with a screwdriver. It only occurs when the front axle is driven (Question:- does it only happen under load or also on the over-run ??).

Having independent front suspension means that the front diff is rigidly mounted (or should be). Are all the diff to chassis mounts OK ?

I once had a tremendous knock on a Volvo Estate when towing horses. Nothing was obvious but one of the engine rubber mounts had come unbonded allowing the motor to rock under load - with the cambox hitting the brake master cylinder. I'm beginning to suspect something like that in this case.

There are a few suspects here (but as you have taken the diff out, any failure should have been obvious).


Front Axle Housing & Differential Assembly - Diagram.JPG


I don't recall exactly how the diff is mounted but check the cross-members involved as well.

The diff may be rocking side-to-side or up-and-down.

Also check gearbox and transfer box mounts - there will be more torque involved when both axles are driven.

A large pry bar will be useful here !

I'll see if I can spot any more straws to grab :doh:.

Bob.
 
Yeah I’m wondering about a mount it does sound rotational but that maybe a red herring. I’m waiting on diff seals to reassemble.
 
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I just can't imagine what spins and could make a noise load enough to turn heads on a motorway without almost instant catastrophic failure .

Could it be like a buckled wheel rattling a worn ball joint which might sound rotational even if it isn't ?
 
Radiator fan makes a right racket if it touches the surrounding shroud .
 
A friend once brought a car to me saying "Its making a terrible noise, I took it to the garage and they listened to it but couldn't find anything wrong".

Front wheel nuts were loose and the mounting holes in the wheel were now oval :doh:.

Sometimes it is just the simple unexpected things.

Bob.
 
I just can't imagine what spins and could make a noise load enough to turn heads on a motorway without almost instant catastrophic failure .

Could it be like a buckled wheel rattling a worn ball joint which might sound rotational even if it isn't ?

It’s only does it under power and I’ve balanced them all recently
 
I’m wondering if it’s a bush that’s moving under extreme load. The seal turned up for the diff so I’ll get it back together.
 
Any updates :icon-question: :icon-question:

This is a really curious one, I'm intrigued. Have you checked all the welds and bolts around chassis/cross-member junctions ??

Really running out of ideas now :think:.

Bob.
 
Well, it's now October 13th and all's quiet.

@billinjah - any updates ?

I'm sort of expecting a transfer box from you, please PM me.

Bob.
 
Well, Bill and I have had some PM correspondence and he has agreed that it can be shared here.

@Shayne and @pradolover90 might be interested as the symptoms now seem very similar to that other topic.

The recent correspondence is as follows (my highlights):

Bill - 23/12 -
Finally got it back together. The original noise has gone it was the front arm bushes. There is a loud noise that seems like something slipping. There is a lot of free play between the output flange for rear and front on the transfer is that normal?

Bob - 24/12 -
Hi Bill,

Transfer boxes are never 'tight', even a new chain has some slack and front and rear shafts are connected via the centre differential planet carrier which also has backlash.

I think I included the list of parts I fitted, it has a new chain, planet carrier and bearings there isn't much else (if anything) I could have done to tighten it up. I would expect 30 to 40 degrees of slop between the output flanges.

Slipping you say . . The only time I have encountered this (after rebuilding the transfer box twice) was stripped splines in a front wheel hub. The Auto '90' would drive on the road but lose drive with a clattering when driven off-road. I have never encountered a slipping chain which is what people normally suspect. If you follow the forum you will see a member in the USA had his drive chain replaced but it made no difference to his 'shunting' problem.

I also think that a slipping chain would chew the sprockets - but I haven't seen that in any of the nine or so boxes I've overhauled. One had been 'off-roaded' so hard the diff planet carrier had shattered.

Is the loud sound you hear associated with loss of drive - all very intriguing ?

I'm afraid these cars are getting old and will never drive like new without a stupid amount of money being spent on them

Its always difficult to advise on a car I've not seen, I'm afraid its a case of hunting down each problem individually. You will certainly understand the car after this !

Regards and have a Very Happy Christmas one and all.


Bill - 26/12 -
No loss of drive it needs more investigation. I’ve had the driveshafts out several times as this has been suggested to me by everyone in the know. I have a video of the noise I could email you. Clutching at straws really it’s been apart on my lift so many times now. I’ve laid under it while someone drives over me and it’s coming from the middle of the drivetrain. But as soon as you remove front prop and lock the transfer the noise goes. So it’s not gearbox.

Bob - 26/12 -
This sounds exactly like the problems that @pradolover90 is having in the USA. He has had the Hi-Vo chain replaced and his knock is now worse.

Would you mind if I put this recent exchange up on the main forum (I don't think there is anything sensitive here) and the collective can apply their minds to both. Hopefully between us we can come to a 'Eureka' moment :icon-question: :icon-question:

What oil have you got in the Transfer Box (should be EP90 GL5) ?

What sort of rotational play is there between the front & rear drive flanges :icon-question: @pradolover90 put a video up showing the play in his and it was less than I would consider normal. I'm interested to hear if yours is similar or worse.

I'll give it more thought.

Cheers.

Bill - 26/12 -
Hi yes ep90 gl5. Before the knock was under heavy load now it’s under light load/continuously. No problem add add to main forum. Have you got an email I’ll send the video.


Bob - 26/12 -
The MOV Vid:

I have the file but its a .mov and I can't attach it (invalid file type) - could someone advise on how to convert it - to what ?? MPEG ? I don't know.

The 'knock' is very evident and unlike anything I've heard before, I can't believe its coming from the Transfer Box as practically everything that wears in there is new. Very strange.

Bob.
 
Well, hopefully I have converted the .MOV file to something that will work here.

What the hell is that noise ????






Bob.
 
It does it under barely any load. The noise before was only under very heavy load. Being under it it sound like it’s coming from transfer box but it’s basically a new unit
 
OK, a bit of a recap and some questions.

The 'clack' noise seems to happen as the clutch takes up the drive, once the truck is moving does it re-occur when under load or only as you go on and off the accelerator (i.e. is there a lot of slop somewhere in the transmission) ??

you say there is a lot of free rotational play between the front & rear companion flanges on the Transfer Box - how much - is it similar to the video that @pradolover put up on this link, or worse ??

Please Help me to figure our if my chain is stretched - [Leaving Land Cruiser Club]


I would say that the play shown above is normal and probably better than most.

This happened with your original Transfer Box but only occurred under heavy load. Fitting my overhauled Transfer Box has made it worse and it now happens under light load. Again, @pradolover seems to have the same issue and replacing his Hi-Vo chain in the Transfer Box made it worse. His is an Auto, yours is a manual, so where is the common denominator ??

Can you drive it on the road? I think it would be a good idea to get someone like Karl Webster to put another pair of eyes on it for a fresh look - two heads are better than one.

When did you last look at the clutch plates, I'm wondering if its coming from the clutch splines / shock absorbers or cover plate.

I'll keep pondering.

Bob.
 
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