o_teunico Posted March 1, 2014 Share Posted March 1, 2014 More vapour build! It is said that 99% of Rover diff failures are caused by pin failure. That is caused by the diff spinning and melting the planet gears to the pin. With two planet gears melted to the pin and the diff trying to spin...bang! Bye, bye pin! Planet gears and pin could be moddified in the lathe and some bearings added (similar to those used in chainsaw engine crankshafts). Feasible or too crazy idea? Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 1, 2014 Share Posted March 1, 2014 I've no idea, it might, but if what you say is true, it suggests that lubrication is inadequate, otherwise the planet gear wouldn't weld to the pin. So an easier solution might be an oilway groove, or using an improved oil, a more modern low viscosity performance oil may provide better lubrication? Fun finding out though! G. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 1, 2014 Share Posted March 1, 2014 There is quite an extensive thread on the LandRover sub forum relating to Lt230 centre differentials and possible ways of keeping them alive. Because the bevel gears in differentials can spend extended periods under load, but not spinning ,the needle roller bearing modification may lead to the needles 'brinnelling' into the cross pin and bevel pinion gear surfaces. Boring the gears out and fitting low friction bushings and modifications to improve oiling may be a better proposition. As weak as early series differentials were, the engineers did do some detail work to the differential bevel gears that later Rover engineers promptly forgot about when redesigning the series 3 vehicles. All the bevel gears on series 2A etc had 3 equi distant oil holes drilled at the base of the gear teeth so that as the gears meshed together, oil would be squeezed through the holes and lubricate the cross pin and thrust surfaces of the bevel pinions and gears. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted March 1, 2014 Share Posted March 1, 2014 Bronze bushes would probably be better, beryllium copper better still..... that'd cost more than a diff however. Quote Link to comment Share on other sites More sharing options...
Boydie Posted March 2, 2014 Share Posted March 2, 2014 When I was driving a semi-works Diahatsu Charade Rally car, early in the cars development differential failure was fairly common, (after all it was a hyped up 1000cc 3 cylinder twin cam turbo shopping trolley), the solution, and to keep the car homologated was to grind a narrow spiral in the shaft to increase oil flow between the gears and the carrier shaft, this spiral was about 2mm wide X 2mm deep and turned a full 360 degrees through the planetry gear bore, we never had any more differential failures once this modification had been carried out. It should work on any car, I must admit I never thought to do it on my Disco differentials, maybe because I dont rev the 300TDi to 11,000 RPM Quote Link to comment Share on other sites More sharing options...
mickeyw Posted March 2, 2014 Share Posted March 2, 2014 I'm sure HfH will be along soon However, my experience of these units failing is not with a cross pin welding to the gears. Normally the locating hole in the carrier has become excessively worn to an oval, thus permitting a backlash situation. Once like this, it doesn't take much for the pin to snap, and the bits to escape, causing further damage. There is also the problem that affects all rover diffs, and that is the crown wheel deflecting under high loads. This is perhaps more of a competition type failure, but quite a common one. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted March 2, 2014 Share Posted March 2, 2014 Mickey, if the locating hole in the carrier is becoming oval is this being caused by the pin spinning? Quote Link to comment Share on other sites More sharing options...
ejparrott Posted March 2, 2014 Share Posted March 2, 2014 Just fit a 4-pin? Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted March 2, 2014 Share Posted March 2, 2014 More complete rubbish. Mo Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted March 2, 2014 Share Posted March 2, 2014 yeah I'd say that will be too much turd-polishing. I've seen them snap just from the wheel getting sudden grip. Everything in the 2 pin design is too weak to be worth doing anything to, especially considering the price of stronger units these days. And I have a very hard time believing that those needle bearings would last in that situation! Quote Link to comment Share on other sites More sharing options...
Blanco Posted March 2, 2014 Share Posted March 2, 2014 Strange I never thought too much about my diffs until this thread, my 110 was fitted with Detroit lockers when I bought it but I have no idea about the rest of the spec. (I assume standard). I did a search and found Nige's very clear video explanation of all the ins and outs of diff architecture on u tube. I don't do competitions but I do do quite a bit of off-road, nearly always towing something substantial and the Detroits have been impressive. Steering not great when all locked up but you expect that. Nearly always its clay in the tyres that brings me to a halt. I think 'shock' loading in competition must account for most of these breakages, for those of us that aren't looking for the limits, the simplest of mods will suffice. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 2, 2014 Share Posted March 2, 2014 Why bother, I mean really why bother? There isn't a good reason to do this in any way shape or form. Just fit a decent diff. Quote Link to comment Share on other sites More sharing options...
zoltan Posted March 2, 2014 Share Posted March 2, 2014 Is it time for a Vapour forum yet? Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 2, 2014 Share Posted March 2, 2014 More complete rubbish. Mo It is not compulsory to read these threads if they are not to your liking Mo. Quote Link to comment Share on other sites More sharing options...
Mr Noisy Posted March 2, 2014 Share Posted March 2, 2014 The welding thing is believable and cross hatching or similar on a carrier pin is not uncommon, saw a nice example the other day but can't remember for the life of me where. But I think the problem generally is the plain simple torque load through the single pin, it simply gets snapped because the diff cage wants to turn and the sun gear/gears don't... Quote Link to comment Share on other sites More sharing options...
o_teunico Posted March 2, 2014 Author Share Posted March 2, 2014 There is also the problem that affects all rover diffs, and that is the crown wheel deflecting under high loads. Diff pegging solves that. the solution was to grind a narrow spiral in the shaft to increase oil flow between the gears and the carrier shaft That looks simple and effective, and does not need any extra parts. I like it! Quote Link to comment Share on other sites More sharing options...
landroversforever Posted March 3, 2014 Share Posted March 3, 2014 This might be useful. Quote Link to comment Share on other sites More sharing options...
honitonhobbit Posted March 3, 2014 Share Posted March 3, 2014 I just use Red Line Hi Impact Diff Oil, over fill and change on a regular basis. I've had one 2 pinion diff fail in 25 years. And that includes clients motors. The diff that failed had 220k on it and was over 20 years old; I was stuck in a gravel stream bed and cadence braking, half shaft snapped and lunched the diff; so driver error... Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted March 3, 2014 Share Posted March 3, 2014 Mr Hobbit.... Is that what Redline advertise as "Shockproof"? http://www.redlineoil.com/product.aspx?pid=44&pcid=8 Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted March 3, 2014 Share Posted March 3, 2014 This might be useful.You don't need that Ross Quote Link to comment Share on other sites More sharing options...
honitonhobbit Posted March 3, 2014 Share Posted March 3, 2014 Yup - heavy shock proof They use to do more grades... I always overfill - just by filling on an angle. Pete Rowe suggested it years ago (along with the Red Line product range). He reckoned that the greatest shock loads on a diff were on a climb; so to give the diff a little help, overfilling meant the pinion was always fully immersed. Pete Rowe is possibly the most knowledgeable LR gearbox man in the Spiral Arm and he successfully ran/runs an 8.4 Olds lump in a !04 hybrid comping; and has done for 25 years or more, so I reckoned I'd go with it. I like Red Line stuff - it's very good. I use the CV grease in all the winches I re-build - about 100 or so a year on average; and equivalent oils in *274's, Husky's and RE's Quote Link to comment Share on other sites More sharing options...
bluespanner Posted March 3, 2014 Share Posted March 3, 2014 My Nuffield tractor has a two pin diff. I notice that where the pin locates in the carrier, it has rollpins to stop the pin turning, which means no amount of wheel spin will make the carrier holes oval. Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted March 3, 2014 Share Posted March 3, 2014 Thanks for the reply... I use Redline GL4 gear oil in my transfer box to meet the requirements of my overdrive. I found no performace difference (Gearchange, noise etc.) compared MTF 94 so stayed with the recommended oil in my R380, but have a recon box going in next weekend.. Will probably go MTF94 unless someone can sell me the virtues of a specific Redline product for the R380. Having read about Shockproof I'll probably use for my diffs at the next change.... Neil Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 3, 2014 Share Posted March 3, 2014 My Nuffield tractor has a two pin diff. I notice that where the pin locates in the carrier, it has rollpins to stop the pin turning, which means no amount of wheel spin will make the carrier holes oval. All series diffs bar the series 3 used a solid pin and a split pin to locate the cross shaft. Rover diffs are a perfectly balanced design in that no single component is stronger than the others. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted March 3, 2014 Share Posted March 3, 2014 Rover diffs are a perfectly balanced design in that no single component is stronger than the others. HAHAHA!! I liked that one alot! Quote Link to comment Share on other sites More sharing options...
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