Having referred to this fantastic forum for a few years now I thought I should start to give back. I found this thread over the weekend following a front diff failure which I can only assume is the type described by bluericky and black wolf. I was about 600 km from home and it being the last week before Xmas was about as bad a timing as it could get. While driving at open road speed 100 kph there were three separate incidents with loud grinding noises combined with serious judder at the front of the vehicle. After the first one I was removing the wheels checking the brake calipers. After the second I was getting suspicious of a transmission failure. The third being fairly certain it was the front diff. Very alarming and stressful with your family in the car. We crawled into our final destination and I begged a local mechanic to drain the oil and check for debris the following day. He confirmed my suspicion and gave me several bolts and bits of gear teeth to prove it. My initial response was to try to get the car trailered home on a transporter but being so close to summer break no one was prepared to do this so it would have been stuck there for several weeks. Instead i opted to try to get myself out of the pickle. I decided to remove the front drive shaft, wheel flanges and drive it home. I thought it may be useful for others to know it can be done. I’m not sure of the forum rules but hopefully “drive without front drive shaft” will show up in searches.

After finding another way for the family to travel home ( I was unsure about whether I’d make it and drove at very unsociable hours departing at 2am!), I removed the wheel flanges and taped around the half shaft to form a basic seal to keep the grease off the brake pads and the dust out. I need to completely isolate the diff unit otherwise it was bound to go bang. Pic below


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I use wheel spacers but you can see the tape behind. Combined with the half shaft oil seals this prevent the diff oil leaking across and this worked well. If oil had started to seep through I would have drained the diff again.

I then removed the front drive shaft. I put the nuts back on the bolts at the transfer case end as they couldn’t come out easily but also seemed to be loose and I didn’t want them wriggling back and striking the case while rotating. Now the diff unit was completely isolated and nothing needed to rotate inside it.

Next step was engaging diff lock the reason for which has been described earlier in the thread.

My last hurdle was TC and Abs which I resolved through a bit of careful trial and error. I have a 2012 110 the first year of the 2.2L. I tried to turn it all off but couldn’t find any instruction in the manual. If someone knows how to do this this would be a useful addition to this thread. I discovered that after driving slowly for a few hundred meters the car would deactivate this itself - confirmed when the warning lights for both of these went solid instead of flashing. The dodgy bit is that up until this point you can feel the TC periodically working all of its own accord, presumably freaking out because something wasn’t right at the front end. It’s not violent but you wouldn’t want this to be happening at any sort of speed. Those of you without TC / Abs will not need to worry about this step but for those who have it be careful!

Anyway I returned the car home without any dramas last night, so that’s 600km at speeds of up to 90 kph. But another warning......I drove extremely carefully as without the front drive the handling is quite different....floaty like you removed the shocks and far from the planted feel it normally has on the open road.

Anyway I hope this is useful for someone else who ends up stuck with a busted front diff.

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

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/

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!

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

blackwolf wrote:

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!

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.

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.

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

karlosgoesbush wrote:

Many thanks Blackwolf ...

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:

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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