 | Home > Puma (Tdci) > Output shaft failure, Forum Survey |
 
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| Bluest Member Since: 23 Apr 2016 Location: Lancashire Posts: 4209   
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The reason for the different splines on either end must surely be that the Ford gearbox could not be provided with anything else as it would be uneconomic to do a special version for Land Rover, and the same would apply to the transfer box. Ideally the MT 82 or the LT 230 would have been redesigned with a male shaft and matching splines so they could connect directly together, no adapter shaft or housing required. But the Puma was a budget overhaul of the Defender, so an ad hoc solution was needed and here we are. I guess one or both gearbox housings would need altering so they could bolt together too, so even more expense.
Can these type of splines be greased by a grease nipple? The inclusion of an inspection cover in the housing and a grease nipple or two on the female end of the shaft might have been a practical solution. 2007 110 TDCi Station Wagon XS |
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2nd Jun 2021 9:09am |
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| Bluest Member Since: 23 Apr 2016 Location: Lancashire Posts: 4209
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That’s a very good point. Possibly the difference here is the shaft is pulled into the splines by a nut or bolt so there is no opportunity for fretting. The adapter shaft splines are effectively floating except for the snap ring with won’t stop movement. 2007 110 TDCi Station Wagon XS |
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2nd Jun 2021 9:11am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17382 
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You would need to consider the aggregate contact area of the two different spline patterns before jumping to any firm conclusions. The LT230 input gear spline will be singificantly more expensive to machine, and due to the small number of contact faces almost certainly has a smaller contact area (and hence lower strength) than the larger splined coupling. Consider also that the part which LR fits to the gearbox mainshaft (the female part of the troublesome coupling) has a conventional design and is significantly smaller in diameter than the coupling which fails. A smaller diameter splined coupling with a shorter spline length is inevitably not as strong than a larger diameter splined coupling with a longer spline length, yet it is always the larger one which fails.
There is no doubt whatsoever in my mind that all three of the splined couplings between the MT82 and LT230 are theoretically of entirely adequate strength for the TDCi driveline, but no splined coupling of any type will last long if the input and output shafts are not coaxial. Any misalignment between the gearboxes or any wear in the LT230 input gear splines or input gear bearings will result in movement in the intermediate splined joint, which will lead to fretting and wear especially in the absence of lubricant. The LOF shaft is probably a very satisfactory solution, provided that when assembled there is no possibility of movement between the shaft and the MT82 mainshaft. If there is any movement at this point, then eventually the splines will fail and the MT82 will need replacement. It is possible that there might be slightly accelerated wear in the LT230 input gear but this is unlikely to be significant. The Ashcroft approach is similarly likely to be satisfactory since it ensures that the coupling remains (wet) lubricated and by so doing avoids the problem of grease drying out and migrating away from the contact surfaces. I would expect either of these to be good and enduring alternatives. I personally would be very interested to see what happens if a vehicle which has a known history of eating these couplings is fitted with either type of upgrade, run for a reasonable mileage, and is then stripped and inspected. As far as I know this has not happened and no data are available. Last edited by blackwolf on 2nd Jun 2021 11:41am. Edited 1 time in total |
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2nd Jun 2021 9:23am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17382
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Yes, if you search on this forum you will find details of just such a modification. At one time I know that at least one main dealer was doing this. All that is needed is an access hole aligned with the nipple on the female part of the coupling. Alternatively there are now greases which have long "wet" lives and which are designed for sliding surfaces, the best known being the molybdenum-based greases. A grease with a high molybdenum content should last indefinitely as long as the matrix doesn't dry out, and will lubricate sliding surfaces very well. I have no idea what the peculiar grease that Landrover used is/was, but it is the wrong colour for a moly grease. When I last changed my clutch, which was about 100,000 miles ago (at a mileage of 150,000) I bought the most moly-rich grease I could find and lubricated the coupling as though its life depended upon it. I do need to fit a new clutch as soon as I get the chance (there is a complete absence of "spring" in the driven plate) and will inspect the coupling when I do, to see how the grease has fared. At 150k miles my original ex-factory coupling was as dry as a bone but had no perceptible wear at all, so it is clear that whatever the problem is that kills these couplings may be, my vehicle did not suffer from it. I changed the LT230 at the same time (due to excessive whining noises) and when I change the clutch I will be putting the original back in. I did wonder if changing the LT230 would affect coupling life, but 100k miles with a lubricated joint suggests not, and this, to my mind, points to the adaptor housing being the variable (I didn't change the housing). |
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2nd Jun 2021 9:33am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17382
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The MT82 is designed to have a propshaft flange fitted to the back of the mainshaft, albeit with a different casing being used to the Landrover version. Clearly (and wisely) the work-experience lad who was given the task of fitting the TDCi and MT83 into the TD5 Defender decided not to redesign the mainshaft, just the casing, which is probably a good thing. An MT82 mainshaft which drove the LT230 directly would have to have an exceptionally long and thin output shaft (or the gearbox would have to be moved a long way back in the chassis and the input shaft would have to be similarly extremely long, but this would seriously mess up the gear lever), and this is unlikely to be satisfactory either, and, I image, would significantly increase the unit cost of the gearbox. As I have said before, there is absolutely nothing wrong with the design theory of the gearboxes on the Puma, but there is clearly a problem with the implementation. |
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2nd Jun 2021 9:39am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17382
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Interesting, this is the first report I have seen of accelerated wear with an Ashcroft coupling. Do you have any photos of the wear? |
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2nd Jun 2021 9:43am |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3414  
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Hi Blackwolf, my 2012 90 has a history of eating shafts every 20kmiles in previous ownership. I knew about it before buying the 90.. made me hesitant? yes, but since price was right, the vehicle met my needs, and I would not be putting so many miles that it would be a frequent (time based) issue, I decided it would be minor issue for me.
As I know, previous owner had replaced the shaft about 40kmiles before my ownership. The splines that normally fail were still intact. When I contacted Dave Ashcroft, he pointed his finger to the bolt at the rear of the mainshaft not torqued to specification. Lot of oil there however!!! As I did not want to strip the gbox, I got a new female coupling from ashcroft. It drives nice, no clunks. I had placed some pictures on this other thread: https://www.defender2.net/forum/topic59735-240.html 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing 2012 90 CSW, 2.2TDCI, Santorini Black |
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2nd Jun 2021 2:10pm |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3414
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About "mainshaft not torqued to specification".. the spec is 180Nm.. This bolt should be tightened to a higher value (example 24Nm), so that the coupling is fully pressed in, and then backed off and re torqued to 180Nm. Possibly when it was done, it was only torqued to 180Nm and possibly the coupling not fully bedded. Then in service it became loose! 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black |
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2nd Jun 2021 2:21pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17382
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Ah, I remember now! I also missed the crucial point that you said "MT82 output shaft splines" rather than coupling splines.
As you say, the torquing instructions for the female part of the adaptor shaft are detailed and fairly difficult if you don't have the special tool for holding the part when torquing to 240/180Nm, and I suspect that a great many are fitted without the procedure being followed properly. I notice that the torque for the LOF solid shaft is very much less than this (only 57Nm), and I wonder if this will lead to similar problems to those you have experienced. |
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2nd Jun 2021 2:48pm |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3414
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For torqueing to 180Nm, I just put the gbox in 1st gear (I saw on Ashcroft site to put in 6th - but that should not be correct). On 1st need more torque at gbox output to turn the engine over. The MT82 should be more than capable of taking 180Nm.
I did not go to 240Nm as the female coupling was not an interference fit anymore. 
57Nm  I am not sure if I would risk that. Bolt is also quite small in diameter, and very long, and as I understood from the you tube videos from forum member Gloucesternige, that bolt is holding some stuff inside the gearbox together.
Somewhere at around 18:00 of this video: 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing 2012 90 CSW, 2.2TDCI, Santorini Black |
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2nd Jun 2021 3:07pm |
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| Julie Member Since: 07 Oct 2017 Location: Nantes Posts: 484  
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Production costs are the reason of plumbing the output shaft like so. That's true. And that's why my 110 will be my last buy from a company acting like so. I'm in favour of cost réduction, no question, but I cannot accept low cost design based on bad engineering. Being an engineer this shaft makes me really sick. The total area of contact faces of the LT230 input shaft is bigger as you have to consider the angle (45 deg) which reduces the résistance to 70% = √2/2 Anyhow, how could you explain the failure of the MT82 output spline if it was the stronger one ? Even misalignement and corrosion cannot explain it, because it effects both splines. It's the MT82 output shaft failing because it's the weaker one. And you cannot design that spline for the rotational pulse resulting from the play in the drivetrain acting like a mass oscillator on the output shaft. |
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3rd Jun 2021 10:07am |
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| islandspark Member Since: 03 Jun 2021 Location: Isle of Wight Posts: 1 
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Hello, be gentle, this is a first post!
I am on Defender number three now, the first two were 110 utilities and were bought new. One was written off the other I foolishly sold at two years. I have read these forums many times but for some reason never signed up as I usually found a wealth of information, or was in a warranty period so some things were not relevant. I now have a "new" 2015 Utility which is great, but has a fairly high mileage of 110k coupled with a total lack of maintenance. Most major parts are as factory and not been disturbed. I have for the last couple of weeks been going through it and working on the many issues, largely drivetrain related and had to replace many parts well past their life. This has included the clutch and of course I was expecting issues with the output shaft, but not quite how I found and considered it to be so important as to mention it here. When the transfer box was removed, there was a lot of red dust and the shaft could be moved around like stirring a pudding. It was obviously about to fail. I am awaiting an ashcroft unit now to replace it with. Earlier I removed the casing from the gearbox to remove the shaft. To my shock and amazement, it has never been installed correctly. It was not in the coupling enough and the circlip had never been back so that it locked in the groove. There is a definitive wear mark where the dust cover has worn the transfer box end and the wear on the teeth seem top back this up. After I removed the coupling, I gave the two parts it a good clout and it went in and locked and the play was now non existent. If I had just picked it up and felt the play I would say it could happily go back in. Assuming when removing the transfer box we had dislodged the shaft and pulled it off the circlip, two of us tried and tried to simply pull the shaft out, but its now locked tight and the removal of the transfer box could not have pulled it out. I firmly believe is never been locked in since new. With the shaft in properly there is now no play as the unworn parts of the teeth are engaged. This is why it clonked and complained all the time, the fact it did 110k on it, I think is a credit to it! Has anyone else come across this? |
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3rd Jun 2021 3:34pm |
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| DSC-off Member Since: 16 Oct 2014 Location: North East Posts: 1404 
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Hi islandspark and welcome to the forum.
Firstly, others have reported that the coupling has parted, or not been assembled properly. Secondly, are you sure it's the original shaft? If it is, then it may be the first 2.2 we have on record of making it past 100,000 miles. Edit: ah, no, there's one more, a 2014 that's done 122K miles. |
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3rd Jun 2021 5:23pm |
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| Julie Member Since: 07 Oct 2017 Location: Nantes Posts: 484
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Hi there, welcome to the forum ! I cannot believe it. You're interested in that unfortunate subject at first 
Once, they began a forum survey representing much data of Pumas concerned or not https://www.defender2.net/forum/post775751.html#775751 |
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3rd Jun 2021 8:02pm |
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