 | Home > Technical > Clunk when reapplying power under light load at high speed. |
 
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20328  
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Probably DM’s and drive flanges, ‘fretting’ is a common issue on the splines. On mine the rear went first.
On there I needed new halfshafts and flanges to the rear. Costly! Or you can go 1 piece DMs instead on the rear. To the front I could get away with drive flanges only, which I did. Is there any kind of movement when the handbrake is applied that’s excessive? That’s a tel tale. For play in the rear driveline. Prop UJ’s are possible too as you say. If you get under there checking the A frame for play can be worthwhile too but doubt so much it is that. That’s the two links to chassis and ball joint, worth taking a look if you do take the trouble to have a look anyway. ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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24th Nov 2021 11:33pm |
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| solarider Member Since: 01 Nov 2021 Location: Godalming Posts: 13 
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Total newbie question sorry, but DMs?
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24th Nov 2021 11:39pm |
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| Ianh Member Since: 17 Sep 2018 Location: Essex Posts: 1997
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DM = Drive member flange. It slides over the half shaft and bolts to the wheel hub. The splines on the drive member and potentially shaft can wear.
Both are a very easy diy replacement. On the rear most go for one piece half shafts |
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25th Nov 2021 12:44am |
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| Grenadier Member Since: 23 Jul 2014 Location: The foot of Mont Blanc... Posts: 5804  
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Don't forget Output Shaft. Type into the search box, huge amounts on what is a very, very well known fault on Pumas. Mine failed (for the second time) just a week or so ago. Based on what you're describing (speed, lifting off and reapplying power, blending the clutch) sounds very similar to how mine failed. Check the other aspects mentioned above (UJs, Flanges, Drive sgafts, A-frame etc) as they can all be done externally, and if they're all tight then OS may be the problem. What KM are you? If you're at 30-40k that seems to be when many fail. Good luck and keep us posted.
https://www.defender2.net/forum/topic62521.html?highlight=output https://www.defender2.net/forum/topic81155.html?highlight=output https://www.defender2.net/forum/search.php...rch_time=0 Monsieur Le Grenadier I've not been everywhere, but it's on my list..... 2011 Puma 110DC - Corris Grey |
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25th Nov 2021 7:43am |
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| solarider Member Since: 01 Nov 2021 Location: Godalming Posts: 13
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37k miles.
Local Land Rover specialist (Keith Gott) thought MT82 output without seeing the vehicle based on my description. That's big money and I was clutching at straws for something else cheaper! The only thing they did say about the output was that it tends to be binary (i.e. it either works or doesn't) and doesn't give much notice, so what I was describing might be something else. |
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25th Nov 2021 10:18am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17362 
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There are so many wear points in a late Defender driveline that a clunk such as you describe could be coming from any one (or more) of many places. The most common (not in any order) are:
output adaptor shaft coupling (subject of many posts but more prone to total failure than knocking) transfer box intermediate shaft bearing wear (more likely to cause rumbling/shrieking noises) transfer box centre diff wear propshaft universal joint wear (four to choose from) or spline wear (two to choose from) differential wear (two to choose from) or imminent failure of front two-gear diff (bad news, can seriously affect control of the vehicle) rear drive flange/halfshaft wear (two to choose from, but the short side (offside) tends to wear quicker) rear "A"-frame ball-joint wear (a classic source of a knock when cycling the power) Suspension bush wear (more commonly rear but front can also cause knocking) rear damper bush wear/failure Something loose in the cabin rolling backwards and forwards (yes, this really has happened) Diagnosing a particular knock under the conditions you describe, but doing so without access to the vehicle, is almost impossible I'm afraid. All you can really do is inspect everything, starting wit the easy ones and working through to the difficult ones. |
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25th Nov 2021 12:11pm |
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| Grenadier Member Since: 23 Jul 2014 Location: The foot of Mont Blanc... Posts: 5804
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Had you posted this after my first OS failure I'd have agreed. But this time round the failure was exactly as you describe up to the point drive became almost impossible and I limped 10k in third gear with serious feathering of the clutch. But the day before I'd driven 500 kms round trip on the motorway. But the previous few weeks had been ever greater clunking on pick up. I knew it wasn't UJs (checked), I knew it wasn't half shafts (changed two months ago), but it was such a gentle worsening situation I thought it was the clutch rather than the OS. You can see from my post (first link I sent you) that I was wrong.  Monsieur Le Grenadier
I've not been everywhere, but it's on my list..... 2011 Puma 110DC - Corris Grey |
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25th Nov 2021 12:59pm |
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| solarider Member Since: 01 Nov 2021 Location: Godalming Posts: 13
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Just resurrecting this with a little more info having crawled under the car. Front prop shaft emerging from the final drive/front dif has quite a bit of play. The rear is sold as a rock. Would this give any further clues?
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18th May 2022 4:18pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20328
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The most significant improvement I found with mine was drive member replacement and universal joints replacement on prop shafts. ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️
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18th May 2022 5:38pm |
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| Co1 Member Since: 19 Aug 2018 Location: North Yorkshire Posts: 3671 
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Do you mean play in the prop bearings/up’s, or just slack in the drive line? If you take the hand brake off on a level surface of course, do you get similar slop in the back when you twist the prop? If so, it’s “normal”. Mine clunked like hell until I had the clutch changed at 75k or so and it’s been smooth as silk since. I’d done drive members, a frame ball joint and pretty much everything else. If you get a clutch rattle when depressed it’s likely the springs are knackered so are providing no damping as you come on and off the power. Mine is a MY13 90. |
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18th May 2022 7:11pm |
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| Smyles_ Member Since: 25 Aug 2018 Location: Copenhagen Posts: 517 
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Check the prop yoke and flange. I had a similar clunk and small jolt that would occur when changing gears and a smaller clunk on lift off. My yoke had eaten away the flange and I'd let it go on for too long so escalate rapidly. Was a cheap fix
 Stuart
Cummins 130 Build Thread 58 130 Double Cab HCPU - Cairns Blue 04 110 Double Cab - Black (gone) 07 Audi RS4 Avant - Silver |
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18th May 2022 10:02pm |
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| 458GT Member Since: 22 Jun 2022 Location: Warwickshire Posts: 83 |
Sorry to bump up such an old thread / the likelihood OP has disappeared, but what did this end up being? Reading your post is essentially a copy of one I was about to make...
Appreciate the answer can still vary, but one is not wishing to go down the output shaft route if it can be helped .... |
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7th Sep 2023 8:45pm |
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