Axle tramp

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ndevans
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Re: Axle tramp

Post by ndevans »

Both engine and gearbox mounts were renewed, I'll check the nuts for tightness.
cheers N

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ndevans
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Re: Axle tramp

Post by ndevans »

Engine mounts checked tonight-1 loose bolt on the n/s mount into the floor, all others tight, apart from a couple that had about another 1/8 turn in them. The rubber blocks themselves are tight on both sides. The engine steady bar is also tight and solid.
I'll check the gearbox mounts at the weekend-need to raise the car to get at them.
cheers N

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RobThomas
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Re: Axle tramp

Post by RobThomas »

Not the exhaust clanging against the crossmember or underside of the boot?
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ndevans
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Re: Axle tramp

Post by ndevans »

I'm pretty sure it's not the exhaust, there's plenty of clearance, though it's a bit tight in places. I will check that by putting some blu-tack on the car, at points where the exhaust is close. Thanks for the suggestion.
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ndevans
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Re: Axle tramp

Post by ndevans »

It's not the exhaust, there is about 15mm clearance between the rear section and the back axle at the closest point, and the exhaust is pretty firm.
There is stuff in the boot, but nothing that I can equate with the sound and feeling I am getting.
It seems to happen when I'm in 3rd or 4th, foot off the gas, and losing speed. It seems to happen at a fairly low speed, say around 25mph in 4th, 15-20 in 3rd. It's almost like the engine is trying to pick up and drive, it definitely seems to be drivetrain related.
cheers N

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paul 300358
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Re: Axle tramp

Post by paul 300358 »

Could you reproduce the clunk with the car held up on axle stands?
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ndevans
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Re: Axle tramp

Post by ndevans »

Not tried yet, but I've had it up on ramps, and there's nothing obviously loose in the rear suspension, diff or cardan shaft. No play in the u/j's, some backlash in the diff, but that's normal.
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paul 300358
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Re: Axle tramp

Post by paul 300358 »

What I was thinking of is putting the vehicle on axle stands and running it in 3rd or 4th to see if you get the clonk, if so, get a mate to listen lying on the floor. Have the front of the vehicle up against a wall.
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ndevans
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Re: Axle tramp

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Hadn't thought of that, there's an idea. Thanks.
cheers N

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ndevans
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Re: Axle tramp

Post by ndevans »

I think you were spot on. I raised the car this evening, and with 2 axle stands under rear axle, ran the engine with the gearbox in 1st, 2nd, 3rd & 4th. The noise I am hearing when driving was most apparent in 3rd & 4th again, and it clearly seems to be coming from the rear axle.
In the videos, you can hear an irregular "clunking". It's not easy to tell from the video, but it's much more obvious from the rear than it is at the front.
https://youtu.be/CTjY85WINfE
https://youtu.be/vCOKL_B-0zc
Is it the diff that's on it's way out? Could it be a halfshaft, or a hub that's gone?
And is it normal for the wheels to seem to rotate a little bit unevenly?

Cheers N
cheers N

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StillGotMy1stCar
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Re: Axle tramp

Post by StillGotMy1stCar »

I’m no expert but have heard similar noises from brake shoes in the past.
Might be worth checking the shoes and springs are fitted correctly.
Regards John
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ndevans
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Re: Axle tramp

Post by ndevans »

What the video doesn't convey is that the clunking can be felt when driving the car. It makes the car shudder, it's almost like an undamped vibration in the drivetrain. Something like that can't just be incorrectly fitted brake shoes, surely?
cheers N

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ianmack
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Re: Axle tramp

Post by ianmack »

If nothing external can be seen to be wrong drain the axle and gearbox oil and see if anything else coes out.
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ndevans
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Re: Axle tramp

Post by ndevans »

I'm thinking the diff and halfshafts have to come out.
Is it possible to move the car without the halfshafts? (Obviously not under its own power!)
cheers N

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StillGotMy1stCar
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Re: Axle tramp

Post by StillGotMy1stCar »

I think I should elaborate on where I’ve heard a similar noise before;-
My other half’s car has rear discs with what is best described as handbrake shoes operating in the top hat area of the disc. I have to adjust the shoes and cable with more slack/freeplay than specified to have a quiet rear end. At slow speeds it is fine.
That is why I thought it might be worth checking your shoes aren’t chattering.
No reason why you can’t pop the half shafts back in drums back on after removing the diff so you can move the car around and retain braking.
Regards John
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ndevans
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Re: Axle tramp

Post by ndevans »

Thanks for the tip.

The rear brakes are standard drums, and I managed, after a lot of time and a few new swear words, to get the beehive springs fitted as well. I will check, but I think chattering shoes is unlikely. The noise appears to be more central anyway, doesn't seem to be coming from the wheel area.
cheers N

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paul 300358
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Re: Axle tramp

Post by paul 300358 »

I would start by removing the wheels and drums then try it again, I would also
ianmack wrote: Tue Sep 10, 2019 6:56 am If nothing external can be seen to be wrong drain the axle and gearbox oil and see if anything else comes out.
You need the half shafts to fit the wheels.
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ndevans
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Re: Axle tramp

Post by ndevans »

Got the cardan shaft off today, and repeated Monday's test. I ran the engine in all the gears, and the was no knocking, clunking noise at any speed. Turning the rear wheels by hand, I could hear and feel the clunking. So I'm thinking the problem lies in the diff &+ halfshafts.
I have a spare diff, which I will try to fit at the weekend. No guarantee it's any better, but I've nothing to lose by trying.

Here is a video of the backlash in the diff, with the handbrake on. Is that too much backlash?

https://youtu.be/UX2Q5BAboXQ

Cheers N
cheers N

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Chipper
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Re: Axle tramp

Post by Chipper »

I would suggest there's rather excessive play in the diff. With the handbrake on, you should only be able to turn the propshaft by a fairly small amount, perhaps a centimetre or so of rotation at the diff flange; you seem to have at least double that, accompanied by quite a clonky sound, perhaps caused by worn crown/pinion teeth.

Also, what is that new looking bracket shown in the video, immediately above the diff?
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ndevans
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Re: Axle tramp

Post by ndevans »

The bracket is actually a rear seat belt anchor!
cheers N

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