robertspark Posted September 30, 2014 Share Posted September 30, 2014 shooting the breeze question as I'm rebuilding mine... Anyone ever broken one? As in, put so much torque through it that it's sheered teeth (either on a gear or off the high / low selector dog splines)? I'm aware of the common failure that Dave discusses on utube regarding not using the diff lock (i.e. centre diff planet (I think) gears weld to the shafts) or the diff lock failure from windup + lack of oil etc. I've got a 1.222:1 (suffix C) and a 1.003:1 (suffix B) and although being tempted to use the 1.003, being a B suffix with narrower input gear and short length input spline, am concerned that it probably won't hold up to the increased input torque (~1500 to 2100 lb ft) in first gear. Note the input gear will be shortly resplined to match my gearbox output shaft (EDM wire erosion). Hence I'm leaning towards the 1.222 with a new input gear (crossdrilled variant) as it has a longer spline length which allows more material / surface area when it's resplined. + has 33mm wide input gear teeth (and not 27mm as on the suffix B). Both 1.003:1 and 1.222:1 have the same number of teeth (26T) in engagement with the intermediate gear (just different tooth profile + gear width). 1.222:1 --> 26T input -> 41/40 - > 31T (41 x 31) / (26 x 40) = 1.222 1.003:1 --> 26T input -> 41/44 -> 28T (41 x 28) / (26 x 44) = 1.003 yes, I know that there is a suffix C onwards intermediate gear (FRC9512) that is compatible with the suffix C onwards input gear (FTC5089), but can't see the point (unless educated on the subject) to fork out the cash on new intermediate + high ratio gearset. Note I'm not sure that if I have a 1.003:1 suffix B gearset (FRC5428 + FRC7432 + FRC7433) if I just have to change the input gear (crossdrilled + suffix C onwards) and the intermediate gear and I could reuse the high ratio gearset (FRC7433) with a suffix C transfer case? i.e. not sure when the change from thick dog to thin dog took place (suffix E)? Thanks for your time Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 1, 2014 Share Posted October 1, 2014 The internet has pretty much decided that they're fairly unbreakable. The figure that's usually thrown around is that they're good for 1000HP. I know Buckon37 on Pirate had some oiling issues on the front output with his, but he appears to have fixed that. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted October 1, 2014 Share Posted October 1, 2014 If I remember correctly mouse used an lt230 I think that's Nuff said. I've never heard of one failing other than wear. Mike Quote Link to comment Share on other sites More sharing options...
dirtyninety Posted October 1, 2014 Share Posted October 1, 2014 Jim Marsden has recently killed a lt230 with ~600bhp I have done something terrible to the internals of my lt230 with just a standard td5 I'm yet to swap it.. and have probably done 10,000 miles since it started juddering. Dumping the clutch at traffic lights isn't a good idea! Quote Link to comment Share on other sites More sharing options...
robertspark Posted October 1, 2014 Author Share Posted October 1, 2014 I'm lead to believe that it's not so much horsepower that kills gearboxes, diffs, drivestafts etc (general drivetrain), but torque, given Horse Power is a function of torque at a specific rpm. Horsepower is also normally over quoted unless someone had it dyno'd (with a calibrated dyno). [like various other appendages.... + fish caught etc] I've heard the 1000HP figure referred to on forums (no factual basis though that I'm aware), but no one has said what breaks at over 1000HP, either. the dumping the clutch seems to normally be the gearbox output spline to input gear wear that is commonly known about, and once the wear (spline play) has started it seems to give a running start (plus clunk) every time you drop the clutch and just makes the problem worse. note -> I'm happy to be corrected + educated if the following numbers + calcs are wrong, thanks for any guidance or correction. If an engine makes 500 lb ft of torque, and goes through a 3:1 first gear, the output torque is 1500 lb ft which in turn is the input torque to the transfer case. Most (factory standard) landrover engines coupled to LT230's seem to have at most seem to have less than 250 lb ft of torque (the 4.6 rover seems to have about 280 lb ft), with a standard gearbox at most around 3.7:1 (maybe 4.0:1 first gear [LT77-50A / LT95], MT82 [TDCi Defender = 5.44:1!!]), so the input torque to the transfer is 1000 lb ft. [on the TDCi defender it's std 266lb ft @ 5.443:1, so round 1450lb ft on the input to the transfer available] a Chevy 6.5 v8 diesel naturally aspirated seem to have about 340 and turbo charged 440 lb ft, but probably run 4L80's (do they??) which seem to have a first gear of 2.48:1, so the input torque rating to the transfer is ~850 to ~1100 lb ft ... seems I may have semi answered part of my own earlier question, will it withstand 1500 to 2100 lb ft of input torque looking at the defender TDCi specs of torque + MT82 first gear at just shy of 1500 lb ft..... but that would be with the LT230Q box.... different gear profile + tooth count on input and intermediate gears, and they seem to have the longer (135mm) input gear .... they also seem to have the 1.4:1 high ratio, so the output torque could be as high as 2,026 lb ft! I guess an engine dyno'd at 475 lb ft with a 3.07:1 first gear (~1460 transfer input torque), with a 1.222:1 gearset will be running about 1782 lb ft output, still below a TDCi defender, and I could maybe add a bit of boost (21 psi) and would be about the same as the TDCi with a 1.003:1 gearset. Anyone aware of any transfer + driveline problems with the TDCi, as those numbers seem huge? I guess again the question remains, other than input spline wear (probably solved with a different spline profile) and center diff failure from not using the difflock, lack of oil + changes + normal bearing wear (and leak from the potential oval intermediate shaft ware on the casing), does anything physically break in them (shafts or gears, etc)? Thanks again for your time Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 2, 2014 Share Posted October 2, 2014 Have a read of this thread: http://www.pirate4x4.com/forum/land-rover/1626818-i-blew-up-my-lt-230-koh-took-me-out.html Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 2, 2014 Share Posted October 2, 2014 The fact that you're having to scratch round for scraps of anecdotes about breakages should tell you something - there's no threads asking if anyone's ever managed to break any other part of LR's drivetrain because everyone knows someone who has. You can break anything if you try hard enough. I'd find something else to worry about. Quote Link to comment Share on other sites More sharing options...
Les Brock Posted October 2, 2014 Share Posted October 2, 2014 Cross pin in the centre diff ? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 2, 2014 Share Posted October 2, 2014 Cross pin in the centre diff ? What about the warning sticker on the fusebox about always engaging difflock when off-road? Quote Link to comment Share on other sites More sharing options...
Les Brock Posted October 2, 2014 Share Posted October 2, 2014 There's a sticker ?....................... Well it "is" possible to break it although it is possible to break just about anything Quote Link to comment Share on other sites More sharing options...
robertspark Posted October 2, 2014 Author Share Posted October 2, 2014 elbekko - > thanks, started reading the post, looks like some good advice on improving oil circulation etc, will finish it off tonight. FridgeFreezer + Les Brock - > it was a shooting the breeze (casual curiosity) question for something that I've always wondered about + see if anyone on what this forum seems to be a really good read + knowledgeable bunch can sometimes throw up where someone will have a bit of knowledge to the rest of us who know little about a lot. I guess as I'm rebuilding the LT230, I was wondering if I could do any simple mods to improve things (which pirate seems to have a few pointers on, thanks elbekko), and also I was going to fit and Ashcrofts LT230 LSD, which is very cost effective in my opinion, but I was pondering over whether it was really really worth it. And how many failures people could throw up considering the centre diff, which at the moment seems very little if you keep oil in it, change the oil in it, aide in cooling the oil in it and use the diff lock on low traction surfaces + prevent wind-up! No one yet seems to have had a gear or dog failure (haven't finished reading pirate yet) from too much torque, (in any ratio choice) and for a transfer case that is what 1970's in the RR classic design seems to be a very low product failure rate (if you use it as instructed + service it). Pirate discussion seems a little negative against the "Q" gearsets (not sure why yet - any pointers much appreciated). Quote Link to comment Share on other sites More sharing options...
robertspark Posted October 4, 2014 Author Share Posted October 4, 2014 Very good read on pirate, well worth it for anyone interested, get a warm brew first and a break 1/2 way through. ashcroft ATB / LSD on order (decision made!), oiling mods / improvement to be done tonight. still not sure about the 1.222:1 or 1.003:1 choice.... Quote Link to comment Share on other sites More sharing options...
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