Popular Post Vogler Posted February 17, 2020 Popular Post Share Posted February 17, 2020 Hi all, I'm currently rebuilding the LT230T 43D of our Td5 Defender after an issue in the transmission which eventually turned out to be in the front axle. Fortunately I enjoy doing this - I've always wanted to do a gearbox and I can honestly say that it is the best way to learn how it works and how to treat it. I also took the opportunity to make some photographs. Initially because the thing looks very nice - it's almost a pity to have to hide it in the casing - but I also realised that I have never seen comparable images. I intended to post these images later because some things should still be improved, but since a member is currently experiencing issues with his CDL, I figured that I already should post what I have. Presumably a lot of forum members know how it works, but for the others I'll try to explain a bit. Feel free to correct or add. Please mind that I have invested quite some effort in making these - so respect my copyright. This is the complete centre differential with shifting forks and output shafts: Here the forks are removed: and now the output shafts too: The large cylindrical volume is the diff carrier which houses the differential gears. The two large gears are the high gear (smaller) and low gear (larger). They each freely rotate on the shaft and as long as the main gearbox is in gear they're driven continuously by the input shaft through the intermediate gears which are not shown. The set of small teeth with large distance between them - dog teeth - are each part of the large sprocket: In between the dog teeth one can see a more finely splined part with a large grooved ring around it - the high/low gear selector ring. The splined part is fixed to the differential housing, and by shifting the selector ring over the dog teeth of one of the gears, that gear will take the diff housing along in its rotation. In these pictures the ring is between the two large sprockets, so the LT230 is in neutral. If the R380/LT77 would be in gear with the engine running, only the two gears would rotate - the diff housing wouldn't. In the following pictures the assembly is positioned the other way round - left and right are switched (one of the reasons I want to remake some of the images). Half of the diff housing is removed, one can see the actual differential. On the left is now a smaller ring over the splined end of the diff carrier. That's the diff lock selector. Again, you see a set of dog teeth, this time they are part of the output shaft (you can see the shafts below). The shafts can rotate freely, so the small differential gears can do their work in compensating any differences in rotation of both axles. So diff lock is off. Here the diff lock selector has moved over the dog teeth. The shaft is now connected to the diff housing. None of the parts can move or rotate in relation to one another - everything is connected as if it is one piece, so diff lock is on: These are just the output shafts and diff gears. You can see the dog teeth on the left. The spiral at the right drives the speedo cable. And here they are relative to the whole assembly (although the gears should be meshing, the main reason why I want to remake the series). Hope you enjoy it and that it can help some people. Greetings, Joris 7 3 Quote Link to comment Share on other sites More sharing options...
toenden Posted February 17, 2020 Share Posted February 17, 2020 Nice pictures! I do, however, not recall my diff being so photographic... more kind of brown/muddy 😇 Well done. /Mads Quote Link to comment Share on other sites More sharing options...
Glue Posted February 17, 2020 Share Posted February 17, 2020 Fab images, many thanks Quote Link to comment Share on other sites More sharing options...
western Posted February 17, 2020 Share Posted February 17, 2020 Nice work, Thanks for posting the photo's certainly help to visulize what goes on in the transfer case while in motion. 1 Quote Link to comment Share on other sites More sharing options...
elbekko Posted February 18, 2020 Share Posted February 18, 2020 Very nice! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 18, 2020 Share Posted February 18, 2020 Awesome! Great shots, must've taken some setting up. The LT230R centre is noticeably different: Quote Link to comment Share on other sites More sharing options...
cackshifter Posted February 18, 2020 Share Posted February 18, 2020 Stunning pictures for posterity. And they might even help me explain to SWMBO how it works. Maybe. Quote Link to comment Share on other sites More sharing options...
Vogler Posted February 18, 2020 Author Share Posted February 18, 2020 Good that you like it. The R sure looks different, thanks for posting that photo! It seems to have considerably larger holes to let oil into the diff carrier. Mads, it didn't look as sparkly when I opened the casing, it was more like the land of Mordor covered in black sticky oil. The last year I did seem to notice more heat coming from the gearbox tunnel. I also made a gif of the diff gear, with an Ashcroft cross pin. Stupidly I forgot to include the copper shims in the pics. The shims were completely gone when I disassembled the transfer box. One can see the circular scratches that the satellite gears made due to the absence of shims. Greetings, Joris 2 Quote Link to comment Share on other sites More sharing options...
western Posted February 18, 2020 Share Posted February 18, 2020 The R at the end of LT230R means it has parallel ROLLER bearings, whereas the T in LT230T means it has later TAPER roller bearings. 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 18, 2020 Share Posted February 18, 2020 This is the sort of shot I expect to see in one of @Shackleton's videos. 1 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted February 19, 2020 Share Posted February 19, 2020 15 hours ago, western said: The R at the end of LT230R means it has parallel ROLLER bearings, whereas the T in LT230T means it has later TAPER roller bearings. What difference can this make? Curious. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 19, 2020 Share Posted February 19, 2020 Intermediate shaft bearings - LT230T at the top, LT230R at the bottom. Personally I think the R looks a better design (much more bearing surface, larger pin to spread load on casing) but I'm no gearboxologist. Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted February 19, 2020 Share Posted February 19, 2020 Might be wrong but a taper bearing will need some preloading to seat everything properly. They're normally used when there are anticipated to be strong radial loads (if that's the right term). Think of a wheel bearing with two taper roller bearings set up opposite each other. If you can picture it a normal roller bearing if used for a wheel would put much more loading onto one side of the rollers than the other. By using taper bearings the load is pushed more evenly across the bearing surface, but you need two of them to sit opposite one another. Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted February 19, 2020 Share Posted February 19, 2020 22 minutes ago, FridgeFreezer said: Intermediate shaft bearings - LT230T at the top, LT230R at the bottom. Personally I think the R looks a better design (much more bearing surface, larger pin to spread load on casing) but I'm no gearboxologist. I'd have thought as the bearings wear on the roller variant you're going to get the shaft wobbling around a lot more and you can't alleviate this like on a wheel bearing by tensioning (which is what I assume the thread is for on the taper version). Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 19, 2020 Share Posted February 19, 2020 True enough Ed, although I wonder if the roller bearings would wear more slowly having much grater area? While we're here, worth noting that the R has yellow metal thrust washers either end of this shaft to take side-loads, and given the LT230 propensity for elongating the hole in the case perhaps the R having a larger shaft and not taking any clamping load through the case would resist that particular failure? Quote Link to comment Share on other sites More sharing options...
Ex Member Posted February 19, 2020 Share Posted February 19, 2020 Roller bearings don't wear.... That is not a failure mode for them. Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted February 19, 2020 Share Posted February 19, 2020 8 minutes ago, Red90 said: Roller bearings don't wear.... That has to be one of the most laughable statements of all time They might wear slower than other bearing types but they'll still wear all the same. The only bearing type I can think of at the moment that will produce next to no wear is an air or oil bearing provided no contaminants get in them. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted February 19, 2020 Share Posted February 19, 2020 (edited) 27 minutes ago, Ed Poore said: That has to be one of the most laughable statements of all time They might wear slower than other bearing types but they'll still wear all the same. The only bearing type I can think of at the moment that will produce next to no wear is an air or oil bearing provided no contaminants get in them. I assume that you do not understand the definition of "wear". Obviously it can happen from contamination. But contamination aside, roller bearing failure modes do not include wear. Overloading or overlife use failures are from fatigue of the metal which leads to spalling of the surface. To the untrained, this may appear to be wear. Bearings are sized to a load and life that will leave them unchanged through their life period and will show not change in dimensions unless this load or life is exceeded as long as the lubricant is maintained and not contaminated. There is no "wear" of the parts. As to the design change shown above, they most likely changed as it is easier to setup the taper roller bearings. There is little thrust load, so the benefit is little from a bearing loading perspective. Edited February 19, 2020 by Red90 Quote Link to comment Share on other sites More sharing options...
Vogler Posted February 21, 2020 Author Share Posted February 21, 2020 (edited) Here's the update on the layered image. This time I also included the bearings: Greetings, Joris Edited February 21, 2020 by Vogler 3 Quote Link to comment Share on other sites More sharing options...
Vogler Posted February 21, 2020 Author Share Posted February 21, 2020 And the whole contraption with the input and intermediate gears: J 4 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 22, 2020 Share Posted February 22, 2020 These are frickin' brilliant and I'm very jealous of your photographic skills! Quote Link to comment Share on other sites More sharing options...
western Posted February 22, 2020 Share Posted February 22, 2020 Super photo's would look great printed on glossy photo paper & hung on garage wall. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted February 22, 2020 Share Posted February 22, 2020 It's excellent work. Is the lt230 derived from the series 1 tonne transfer box? It looks kind of familiar... Quote Link to comment Share on other sites More sharing options...
western Posted February 22, 2020 Share Posted February 22, 2020 1 hour ago, Gazzar said: Is the lt230 derived from the series 1 tonne transfer box? It looks kind of familiar... In fact the original transfer box principle, albeit without permanent four-wheel drive, dates back to the Series I of 1948. mentioned in https://www.autoexpress.co.uk/land-rover/range-rover/100624/lt230-the-best-ever-transfer-box Quote Link to comment Share on other sites More sharing options...
Gazzar Posted February 22, 2020 Share Posted February 22, 2020 It's the middle gear on the intermediate shaft, that's very like the 1 tonne. Quote Link to comment Share on other sites More sharing options...
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