29 replies to this topic

[nicklouse]

Open up the diff. In the second vid the crown wheel can b seen moving but the drive flange is not. The one on the other side should be moving at twice speed. But it is not shown. But the whole thing looks to be very stiff to move.

[Lplus]

Having watched the videos, I'm wondering if there's a piece of metal jammed in the base of the vee between two teeth on either the output pinion or another gear always turning with the output shaft which turns at the same speed as the output pinion.  (reverse idler?). It wouldn't need to be a large piece of metal, just enough to bottom out the opposing tooth when it hits it so it needs a bit of force to get over it.

 

Yeah, I know, have some straws to clutch at....  Still, nothing else makes sense to me. :shrug:

[Spider]

I'm just wondering here if it is in the diff, a split planet gear, worn pin. Put it in to a gear (any gear), grab and hold fast one output flange and see how much the other can be rocked from one point of stopping back to the other. More than about 10 degrees of movement and the diff is pretty worn.

In you first video where the output plant isn't turning, the diff is in fact being being worked. If the flange was spinning with it, then it would be not worked.

If you are looking to do this with the minimal amount of work, you could drop the diff out to examine and overhaul it. If it was me, I'd be dropping the whole box off to further examine it, even if it is just the diff, you'll al least want to clean out the box and check it for shrapnel.

[Lplus]

I'm just wondering here if it is in the diff, a split planet gear, worn pin. Put it in to a gear (any gear), grab and hold fast one output flange and see how much the other can be rocked from one point of stopping back to the other. More than about 10 degrees of movement and the diff is pretty worn.

In you first video where the output plant isn't turning, the diff is in fact being being worked. If the flange was spinning with it, then it would be not worked.

If you are looking to do this with the minimal amount of work, you could drop the diff out to examine and overhaul it. If it was me, I'd be dropping the whole box off to further examine it, even if it is just the diff, you'll al least want to clean out the box and check it for shrapnel.

On the basis of those videos the box is already off.  Whatever is happening is only happening every revolution of the output gear.  Would a diff internal fault do that?

[lildeucecoop72]

Right thanks for all your replies, and sorry its been a bit quiet. There has been some development here. This is a long long post, I'm afraid.

So I removed the diff back cover and side covers for the output shafts, and then upon turning the diff, the sound/feel of the clack stopped....(sort of, read further).
I visually inspected everything. There are no marks, or damage on the diff itself, bearings or on the covers, no loose or foreign materials that i can see either.
At first, I was elated about the sound stopping, but when putting the covers on again (but particularly not tight) I could not get it to re-create the clack sound as before, which was really frustrating. I was turning the output shafts in unison as before on the diff, quite fast and hard hard at this point.

So I decided to 'reinstall it', with appropriate bolt torque and shimming to try to see if I could at least re-create the clack sound again.
I placed and tapped the diff assembly against the side cover (toward the flywheel side as before).
I then put the diff back cover on, and tightened bolts so that they just-nipped to hold everything in position.
I put on end cover (non flywheel side) on with same shims as before. I tightened both side covers so these also just nipped, and turned the diff....

This re-created the clack sound as before! YEAH! - OK, But I still couldn't see the cause.
I decided to test further, and after removing a cover (one or both) this SEEMED to stop the clack, so removed all diff bearing shims...


NO Clack again! (well sort of...wait for it).

I started to add diff bearing shims again one by one, and put the end cover on after each time to test until the clacking appeared. Shimming greater than a thickness of 1.14mm results in the NOTICIABLE clack/with bump again.

However, with each shim I removed, and while carefully and slowly turning the output shafts together, this revealed there was actually still a clack/bump, but it got 'weaker' with every shim I removed. I thought this would solve it - that I had incorrectly shimmed it. Though this did not explain why the clacking sound had suddenly started in the first place, and after 14 years of driving since the diff went in with no sounds or probs.

I removed the covers to try and go the other way - to build up the shims to find the 'tipping point' where the clacking starts. Whilst attempting this I took the side cover off (non flywheel/passenger side) and when turning very slowly the clack and locating 'bump' was still evident! . OK then, I thought, and I removed the other side cover and got the same result (both covers now off)!!
The 'clack/bump' was very very weak, almost unnoticeable, but still there, none the less.
I then removed the diff back cover, and when turning whilst it rested on the gearbox case, no clack - So there needs to be pressure from a casing somewhere to cause it.
I then removed the diff for inspection. Its a 4 pin type. The output shaft for the hardy spicer on the crown wheel side has play (more play than other diffs I have seen)
I am not sure if its the play in the diff or the bearings or a combination. When turning it, i found it to be a bit noisy, again more than other diffs I have looked at.
I also turned the bearings, these went around smoothly, though one (the same side as the loose outputshaft) seemed to be slightly more rough under pressure.
So as mentioned, the cause of the actual clack sound is still a mystery, but the diff seemed a bit worn to me (I am no expert and I dont have another 4 pin diff to compare it to).

To try to rule them out with the diff removed, I turned the gears themselves and these seemed to be fine. no motion problems, no clacking - I have yet to check all the gears, but I am confident these are OK, unless it the pressure of the diff being in place is the actual causes and the sound comes from the gears. I could test this by bunging in another (2 pin) diff I have lying around to check that.

After having a little think I remember there being a struggle when putting one of the HS (Hardy Spicer) driveshaft flanges on to the HS output shafts together back in autumn of 2021 to (the angle seemed to be slightly off). It was really hard to mate up and seemed not to align properly. In the end I 'forced' this on and tightened the 4 flange bolt nuts - I guess this could this have moved something or damaged something in the diff that got worse as I drove the car?

The next step is to open the diff itself and check for wear.

Has anyone had similar problems?

Cheers :)

Edited by lildeucecoop72, 11 January 2023 - 05:12 PM.

[lildeucecoop72]

OK it seems to be the bearing nearest the crown wheel could be the cause. after removal and a clean it seems to roll, but hit notches.
This in my mind still doesn't seem to account for the violent clunk sound and notchy feel.

I have an old standard diff which has some old bearings still on it, I put that in to test. No clunk. 

I then tried the one of these old bearings on the crown-wheel side my diff to replace the notchy one. I put that in and shimmed and torqued. No clunk.  So I guess thats it.

 

Unless anyone else has som observations I think this is solved. But again weird that such a massive amount of feel and sound can come from that and intermittently. I would have thought a bearing prob would be constant.

 

Again thanks for your help and replies.

Edited by lildeucecoop72, 02 February 2023 - 10:30 PM.

[Spider]

It sounds to me here like one of the diff bearings has badly pitted or cracked.

[lildeucecoop72]

Yupp, the red marks show where the the inner race is pitted.  If you look carefully, you can see extensive damage. The pitting lines-up with the ball bearings. There is also one area of the outer race that is badly pitted. I think when these 'lined up' under rotation, this caused the seemingly 'random' clacking sound (as the bearings were under pressure from diff/end covers and shims).

 

So how did it get that way? It can't be from driving, as this would give constant wear.

 

My guess is that when I drained the oil, the engine/box (and diff) was standing about for a while (18 months) with temp and humidity changes. with no oil or grease (I had flushed with petrol) around, perhaps condensation formed under the ball bearings. These turned to rust, and etched into the race, and then flaked off when turning the diff on the stand  causing the pitting.  This would also explain it suddenly happening.

 

I also went for the cheaper bearings (RLS) 14 years ago when I changed. I am not sure if there is any difference in quality but it looks like most people seemed to think RHP are a better option. Though, I admit that this might well have happened with RHP bearings too, under the circumstances.

 

I also found similar damaged on the dreaded transfer gear shafts, so that will need changing too!

Moral of the story: Keep your gear lubed!

 

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Edited by lildeucecoop72, 02 February 2023 - 11:21 PM.

[Spider]

Yes, they are well razzed. They do appear to be an etching type failure, most likely from rusting.

 

How have you got your Crankcase Breathers hooked up ?

[lildeucecoop72]

Yupp - but I am glad I found the problems. Means I can get on with the repairs so she is ready for spring.

 

Regarding the breathers. Separate breather filters on the crank case (A+ type), and clutch case.

Why would that make a difference?

Edited by lildeucecoop72, 03 February 2023 - 07:10 PM.

[nicklouse]

Yupp - but I am glad I found the problems. Means I can get on with the repairs so she is ready for spring.

 

Regarding the breathers. Separate breather filters on the crank case (A+ type), and clutch case.

Why would that make a difference?

What are they connected to? 

[Spider]

 

Yupp - but I am glad I found the problems. Means I can get on with the repairs so she is ready for spring.

 

Regarding the breathers. Separate breather filters on the crank case (A+ type), and clutch case.

Why would that make a difference?

What are they connected to? 

 

 

As Nick has asked, how are they connected up ?

The Crankcase Ventilation System in either PCV or CCV for in part, removes moisture from the Crankcase. If they aren't connected or there's an issue with the system, moisture builds up in the oil and in the crankcase, it forms acids (that attack bearings in particular) and causes loads of rusting.

[lildeucecoop72]

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I have one if these mounted on top of each standard breather pipe/bracket. I can post pictures from the car if needs be.

[nicklouse]

That will be part of the problem.

Best to have it connected as per original or similar so that the water vapour is removed from the engine rather than is condensing in the engine oil and then causing rust. Along with the other chemicals you don’t want.

[lildeucecoop72]

Thanks, good to know. The car came with this set up so been driving around like that since 2007 thinking it was fine.

I’ll check out the best solution.