Snagger Posted March 17 Share Posted March 17 16 hours ago, Gazzar said: Yet another overdrive. I'll strip this Monday morning, see what I've got. It does turn. And very little play.... Cornering the market! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 17 Author Share Posted March 17 The scrap over drive market..... 1 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 17 Author Share Posted March 17 Unfortunately. I've been thinking. How could these overdrives be improved? I mean modified to be better, not a new design or anything! Are the layshaft teeth wearing because the layshaft is too close to the mainshaft? It's possible to mill a new casing, or part casing to move the layshaft. So that's feasible. You could even cut the casing and insert a spacer plate to move the layshaft part further away by 10 mm. What layshaft or gearset could be made work with the input and output gears? Even if the output gear was ground off the shaft and a new one splined on. Again, not easy, but feasible, with wire spark erosion equipment. Ditto, I suppose, for the input gear. Damn it, I need to stop thinking. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 Beauty! 4 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 As I've now got a larger selection of parts I'm re-examining the bits I rebuilt the overdrive with the first time. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 First, the main shaft. I've a better one now so that's going in. Less wear on the input gear bearing surface. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 Next, the output shaft. The first one has tooth cavitation against the layshaft. The second has syncro damage. The third has surface corrosion on the output gear. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 The third one going in, as the transfer box gear is available, should it wear. Plus the lubricant is better for this gear set. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 Ah. It wasn't the layshaft. It was the input gear. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 And I've not got a good one of those, or so it would appear. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 And, so a bodge. The macro lens showed a crack and, as the last thing I want is bits of metal rumbling around in the overdrive I ground back to the good metal. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 Well, it feels okay now, so I've buttoned it all up and will do the selector stuff in a minute. Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 18 Share Posted March 18 Did you take a really close look at the tooth adjacent to the one you dressed? Looks suspicious to me. 1 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 Damn. No, no I didn't see that. I'll strip it down again..... Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 Not visible to my eye, but the camera picked it up. Macro lens Anyway, I've dressed that up as well, and reassembled the thing. Including the selector rod, but not detents, yet. I've done enough for today, turned my back on the mess and walked away. I think I've a decent overdrive, bar the input gear, and that will have to do. Such a shame no one is making new parts for them, but no demand, I suppose. Why do they fail ? Weak design or lack of lubricant? The overdrive is above the transfer box filler so must rely on drip lubrication. What's the problem with overfilling the transfer box? It's got a breather so it won't blow the seals. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 18 Author Share Posted March 18 @Snagger Thank you Nick. Appreciated. Quote Link to comment Share on other sites More sharing options...
B reg 90 Posted March 18 Share Posted March 18 Have you considered checking the gears for cracks with dye penetrant? NDT Test Kit | Weld Defect Dye Pen Kit | Cleaner, Dye Pen & Developer (tbws.co.uk) Dead easy to use and will give you a much better indication than you can see with eyesight. Ideally you would use fluorescent DPI, the rattle can basic version will do for your task. Adrian 2 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 19 Author Share Posted March 19 I did, but thought it would be out of my reach. Thanks. Quote Link to comment Share on other sites More sharing options...
garrycol Posted March 19 Share Posted March 19 9 hours ago, Gazzar said: The overdrive is above the transfer box filler so must rely on drip lubrication. What's the problem with overfilling the transfer box? It's got a breather so it won't blow the seals. The two scoops on the O/d housing catch the Tfr case oil as it is splashed around and feeds into the O/D. So if there is oil in the Tfr case there will be oil in the O/d with its own sump. However at fill, the O/d and the tfr case needs to be full - the best way of doing this is to remove the filler plug at the back of the Tfr case and remove the filler on the O/d. Fill through the O/d until the oil runs out the Tfr case filler - both will be full of oil. I got my O/d on the back of a Stage 1 LT95 in 2008 and moved it to my 101 - has never been a problem and not noisy even though it has had a hard life. Garry 2 Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted March 19 Share Posted March 19 4 hours ago, Gazzar said: I did, but thought it would be out of my reach. Thanks. I'll send you a dye pen kit down Regards Stephen Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 19 Author Share Posted March 19 Noooooo!!!!! I'm NOT rebuilding this again!!!! Thanks, I appreciate it. I do wonder if there's ANY new stock or out there? Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 19 Author Share Posted March 19 @garrycol that's good advice. I do wonder why so many of these units are wrecked, could be poor maintenance? Aggressive driving in a range rover? Or just a weak design. The series unit was never great. Quote Link to comment Share on other sites More sharing options...
garrycol Posted March 19 Share Posted March 19 The Lt95 Overdrive is different to the Series unit. It is much stronger and reliable than the series unit. On my first trip with the O/D fitted I did not have the linkages fitted and drove 500km with the O/D operating - in all gears, went to a 80km long beach with 50m high sand dunes and climbed most of them and then drove 500km back home - all with the O/D in and a mix of high/low revs, hi/low gears and high/low range - not a murmur from the O/d - it was only when I went to fit the linkages that I realised the O/D had been in all the time. Now I only use the O/d in 4th gear - not any of the others and I think this is wear is happening - using the O/d in all gears, reving the guts out of them - also even though the O/D is supposedly synchro I always - always double shuffle the gear changes (pausing in neutral with a corresponding clutch movement - hurrying the changes will cause crunching where double shuffling does not. So the O/D is inherently strong, is well lubricated if the tfr case has oil, but it does not like to be shifted with urgency. Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 19 Share Posted March 19 Sorry that my suspicion turned out to be right. I suspect that the damage was caused by neglect and binary clutch and throttle control. I wouldn’t be surprised if something went through the gears, perhaps a piece of the transfer box it had been fitted to. I don’t want to seem like I’m taking the pee, but the new photo makes me suspect the next (third) tooth too. That is enough to make me suspect they all have similar damage, which would be very plausible. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 19 Author Share Posted March 19 I checked the rest under the macro lens, didn't take photos, but nothing showed up. Initially I thought a few were fractured at the root, but it was a witness mark in grease! 1 Quote Link to comment Share on other sites More sharing options...
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