![]() | Home > Puma (Tdci) > Broken spline in axle housing |
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LR90XS2011 Member Since: 05 Apr 2011 Location: bickenhill Posts: 3665 ![]() ![]() ![]() |
that is a useful get me home technique
however following Blackwolf's previous threads I upgraded to an Ashcroft ATB front and rear, feel much more confident now that I wont have a catastrophic diff failure, car is much better for them in many ways. (99.9% road use) DEFENDER 90 TDCI XS, I hope everyone is well and your land rovers make you happy |
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Bluericky Member Since: 26 Jun 2014 Location: Cornwall Posts: 647 ![]() ![]() ![]() |
That’s bad luck but glad you got home in one piece .
If only there was some warning before failure , mine just went while turning on hardlock on the driveway ! https://www.instagram.com/hustynminepark/ |
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blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17731 ![]() ![]() ![]() |
A useful post, and it is clear that your mind works in a similar way to mine. I actually find that most of the time I am driving my Defender I am running though the "what do I do if ... breaks" or "how do I drive home if ... has broken" and have run though in my mind the exact scenario you encountered before now.
I think if conditions permitted and you had more time, or if you had a long way to go before you could sort it out properly (think Australia outback, Africa, etc) you would probably be better off taking out the front halfshafts and CV joints, but it is not trivial. The tape-up-the-hub technique is clearly fully viable. I have also considered boring out a pair of old drive flanges to remove the splines (and possibly even putting a brass or bronze bush in them) so they could be fitted in this eventuality, but it seems a bit extreme just on the off-chance. It is strange the way an engineering mind occupies itself when driving a Defender! |
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LR90XS2011 Member Since: 05 Apr 2011 Location: bickenhill Posts: 3665 ![]() ![]() ![]() |
I spend most of my time wondering what that noise is and when its going to break,
having said that it has never actually broken and let me down, probably because I have replaced all the usual weak links in the system with the help of this forum DEFENDER 90 TDCI XS, I hope everyone is well and your land rovers make you happy |
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karlosgoesbush Member Since: 05 Jul 2016 Location: Wellington Posts: 4 ![]() ![]() ![]() |
I agree that for a long haul home properly sealing the wheel bearings is important to prevent dust ingress and oil/grease egress. I think the thing that worked in my favour was that nothing was rotating inside the diff. I expect the ends of the half shafts may have a few bruises due to knocking up and down inside the housing (normally supported by the wheel flange), but I've yet to inspect. Rough roads up the East Cape! Anyway, now I need to order an Ashcroft rebuilt P38 with ATB and heavy duty ring / Pinion to match the same I stuck in the rear a couple of years ago c/o this forum. My only reservation is that either the ATB or the heavy duty ring/pinion introduced a slight whine - not all the time - only at high speed and only with the foot off the gas pedal. I'm not sure which new component was the culprit. And then the question of whether to change out the half shafts and flanges for Ashcroft heavy duty. The rears I put in a couple of years ago are worn, not as fast as the stock setup but nevertheless now a bit sloppy which was unexpected. Perhaps I am to blame for not regularly replacing the grease but there is no sign of any rust colour under the caps and I am one of those 99% on-road Landy owners so not crossing rivers etc. Backlash remains on my "fix it" list. And as we know as soon as there is some backlash this leads to more accelerated wear and rapid onset of more. Has anyone tried modifying a drive shaft to put in one of those rubber donuts like on the old Rangies and Discos? Yes it introduces a weak point but if easy and cheap to replace regularly and if it takes the transmission clunk hits and makes the down shift gear change-followed-by-acceleration smooth, then I'd be up for trying it. Besides which if its good enough for an old V8 then surely okay for puma engine? Apologies, I digress. |
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blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17731 ![]() ![]() ![]() |
Remember that it isn't a P38 in the front, it's a Rover pattern diff.
I have an Ashcroft ATB with HD R&P in the front of mine, but it does give a very slightly different ratio to the rear (there isn't - or at least wasn't - and HD R&P option for the P38 in the rear when I built mine up). The difference in ratio doesn't seem to matter, mine has done well over 200k miles now in this configuration. My front diff was supplied as a built-up unit by Ashcroft Transmissions after my original 2-gear diff self-destructed and did whine initially, but after a few thousand miles became silent (or I became deaf to the specific frequency, possibly). Usually I build my own diffs and I have never (yet) had one that whines, so it may be due to the HD R&P. Remember that the Puma engine develops significantly more torque than the V8. |
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karlosgoesbush Member Since: 05 Jul 2016 Location: Wellington Posts: 4 ![]() ![]() ![]() |
Many thanks Blackwolf. Yes my mistake, I need the Rover type for the front.
And since I am correcting my mistakes, it was this ring/pinion that I have on the back: https://www.ashcroft-transmissions.co.uk/r...27528.html But that's not the H/D and remains 3.54. At the time I assumed that since it wasn't stock it was H/D. Must be Ashcroft's version and presumably better but not H/D. So, the diff whine must have come from either the ATB or it is due to something not being done right by the transmission specialist I paid for the rebuild. Anyway for the front I have ordered a rebuilt diff with ATB (now called TBC on their website), so after I have fitted it myself using your very helpful posts where you keep the wheels, brake calipers etc on, I will be able to feedback on whether there is a second whine. Re the donut, yes I suppose the V8 is all about power but necessarily torque. I drove my mates TD5 the other day and could hear all of the backlash being taken up each gear change but it was much easier to drive smooth. It definitely had much more slop but it wasn't as noticeable. This must be due to the difference in torque at low revs. I've thought about this a bit......driving the puma feels a bit like you are trying to crash-start (a southern hemisphere term I hope is familiar to you) when accelerating after changing down from 3rd to 2nd in particular. My puma has the BAS170 remap so this effect is perhaps slightly exacerbated. I've also thought about asking BAS for a modified remap with reduced torque at low revs just to see if it makes any difference. But there I go again off on another tangent. Thanks again for your comments. |
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LR90XS2011 Member Since: 05 Apr 2011 Location: bickenhill Posts: 3665 ![]() ![]() ![]() |
this is an interesting thread on mine (2.4) I now have very little transmission slack as I have modified most of it out,
I have recently fitted 1 piece rear half shafts from a disco 1 they made a big difference even though the 2 piece ones had minimal play. (I don't off road and they are performing fine so far) However it is very evident that the throttle responses are damped on mine. for example if you are just cruising along and lift off the throttle the response is not immediate but steady and the same if you then plant your foot, it is as if the fly by wire via the DCU is designed to protect the transmission generally I can now only create a clunk in the transmission with the clutch, and that is now much reduced with a LOF clutch. I did wonder myself about some vibration/clunk reducing disco mods but have done none of them 1/ rear rubber coupling rather than u/j (yes weaker) 2/ harmonic damper on front diff (would this work front and rear to remove some of the wining from diffs) 3/ rubber spring seats (but I don't want a lift so will fit in the future with lower comfort springs) DEFENDER 90 TDCI XS, I hope everyone is well and your land rovers make you happy |
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blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17731 ![]() ![]() ![]() |
You're welcome. I have the same setup at the rear (3.54 original R&P with ATB) but the front is an ATB with the Ashcroft 28/8 3.5 ratio R&P. If I were to replace the rear again I'd probably go for an Ashcroft long-nose with ATB and 28/8 R&P. I think the whine is always a function of the R&P set-up rather than the diff itself, and is generally caused by incorrect pinion engagement, either the pinion height or backlash being not quite right, or tooth characteristics or wear in the tooth profile (assuming that the pinion and carrier bearings are good and the preload is correct, of course). Drive line backlash is a characteristic of the TDCi, and personally I think that the number of wear points combined with an unusually "binary" clutch is the reason. Over the years and miles my driving technique has evolved to compensate for this, but the well-discussed lack of effective springing in the clutch is key. Modern high-torque, low-inertia (hence vibration-prone), high-revving diesels are brutal to clutch damping, hence the reason most have DMFs, and really we just have to live with it. I also have the final type of genuine one-piece rear halfshafts in mind (absurdly expensive but they really help the lash). Would you believe the country of origin of these is South Korea? They probably came from the Kia factory! |
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karlosgoesbush Member Since: 05 Jul 2016 Location: Wellington Posts: 4 ![]() ![]() ![]() |
After a long wait for the part (but being very grateful for it in this COVID era), I have fitted the new front diff. It is an Ashcroft rebuild including their ATB and normal 3.54 R&P.
Needless to say it is fantastic to have it back on the road and the ATB on the front definitely feels different. It has a self-centre effect on the steering, which is minor and you get used to quickly. I don't mind this one way or the other, but some people may not like it. The Ashcroft website says this effect reduces after a few hundred miles. On the plus side, it feels more planted and although I've yet to test it off road I reckon it will be an awesome addition for traction. I already have an Ashcroft ATB in the rear so with both, and with TC, I expect a significant gain in slippery conditions and cross-axle situations. The most important benefit I've noticed so far is on the road. Previously, at highway speeds i.e. 100 km/h, if the front left wheel dropped into a dip or hole in the road surface, there was a minor self-steer effect to the left, which most of us would correct without even thinking about it. I think the vehicle being relatively top-heavy exacerbates this due to body-roll. However, with someone not so used to driving these beasts, it can get ugly quite quickly at these speeds especially if they over-correct (closest I've come to rolling it with the better half driving). The ATB seems to have eliminated this effect, and hence I think is a significant safety improvement. I have used a synthetic diff oil, which after reading the Ashcroft site is not recommended so I will change it out for a good quality mineral equivalent (Dave from Ashcroft said it wont have done any harm, but the ATB works best with mineral and no additives. A transmission specialist rebuilt my rear diff a couple of years ago and there was a strict break-in regime.......not over 80 km/h and light loading for 300 km. Then an oil change. There is nothing on the Ashcroft site about this. Does anyone have any advice here? I suppose the prudent thing is to do the same...trouble is I've already broken those rules being so stoked to have it back on the road! Insofar as the diff failure is concerned, it was not as expected. Based on your earlier comments, I thought it would be due to the diff centre pin wriggling out of an elongated hole in the casing, but this appeared to be okay. What let go were the ring bolts - specifically the bolt heads break (or being ripped) off.. Dave said they see this type of failure regularly. I have no idea what the root cause was - perhaps all it takes is a single bolt to let go? One bolt head rattling loose would then start to break off gear teeth and then other bolt heads. Some pics: ![]() Click image to enlarge ![]() Click image to enlarge ![]() Click image to enlarge ![]() Click image to enlarge ![]() Click image to enlarge |
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Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3542 ![]() ![]() ![]() |
Personally not a fan of grade 12.9 bolts.
The problem with 12.9 bolts is that they can handle a lot of stress but not strain. In applications where several bolts are used to fasten an assembly, I personally prefer bolts that can handle strain a bit better, so the load can be more evenly distributed. Just my 2c worth. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing 2012 90 CSW, 2.2TDCI, Santorini Black |
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