Peaklander Posted January 13, 2022 Share Posted January 13, 2022 I had to remove my Roamerdrive in order to remove the transfer-box to do what I hope is routine maintenance after 170K miles on my 110 300TDi. A few months ago, when the OD was last engaged, I thought I was starting to hear a noise and it's been in my mind to investigate. However I have continued to use the vehicle for local journeys. Here is a video taken today straight after removing the unit. I am assuming horrible things are happening inside and I will need to open it up, hence this thread. Quote Link to comment Share on other sites More sharing options...
western Posted January 13, 2022 Share Posted January 13, 2022 Worn bearings maybe. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 13, 2022 Author Share Posted January 13, 2022 (edited) Hi Ralph, yes I assume so. I know there's details around that explain how to work on it. I will dig them out but I have also sent the link to Ray in Vancouver to see if he has any feedback overnight, UK time. Edit: I have found this thread which is a great start, with plenty of input from @Snagger Edited January 13, 2022 by Peaklander 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 14, 2022 Share Posted January 14, 2022 The bearing sounds very rough, and the front taper bearing looks worn out. I would expect a complete set of decent new bearings to sort everything out. Like I said many times, they shoot themselves in the foot by making a very well designed product and then using cheap, dismal Chinese bearings. 1 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 16, 2022 Author Share Posted January 16, 2022 Whilst I think about whether to do the LT230 overhaul / upgrade myself or ask Mr Ashcroft to send me an exchange unit, I cleared the bench and started to look into my Roamerdrive. The only problem that I have had with this was in the first few long miles with it engaged, driving through France. I had been unable to deselect it as it dropped into a 'neutral' position. I had needed to stop before it would engage. That was found to be a rose joint vibrating loose and lengthening the selector rod. The effect of that was to reduce the allowed travel between engage and disengage. SInce then, it has behaved perfectly until recently it began to sound 'noisy'. As I was removing the Transfer Box I had to remove the overdrive anyway and as soon as it was on the bench it was clear that something was amis, as featured in the clip posted above. I have started to dismantle it and pulled the front of the case to allow access. Almost straight away I began to find pieces of metal. Three cap-head screws to release the front cover Can already see metal in the wrong place... The rear housing with selector fork and synchromesh ring etc. Releasing the selector rod Then the detent housing with spring and ball The selector fork and dog? gear came out and the synchro ring. This has lost all the fine grooves on the inside face; it's polished smooth. However various parts popped out too, and that is as far as I have got because I need to undo the six cap head bolts in the rear face which are tight and imperial size. The imperial allen keys that I have are quite short but at least they are in (what used to be) an appropriate tin. That bearing at the rear sounds even rougher now. Edit; Oops, I forgot the all important pic... 1 1 Quote Link to comment Share on other sites More sharing options...
western Posted January 16, 2022 Share Posted January 16, 2022 Hope your able to get all the new parts you need. 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 16, 2022 Share Posted January 16, 2022 It was the rear bearing that failed initially on mine. It still turned, but the races and balls were heavily worn and pitted and allowed longitudinal movement of the sun shaft. That crushed the needle bearing on the sun shaft, skewing the needles so they seized on the shaft and bore. The haft bearing surfaced needed turning and sleeping, and the e gods of the teeth needed dressing where they had contacted the planet carrier, but your shaft and bearing look fine, so you probably got away with it. Not sure which bearing has disintegrated. The shim has me curious - the series model doesn’t have those, but the series box main shaft end float is set by the main bearing in he box, not the bearings behind the transfer case, so I suppose the Defender version has some thrust bearings as well as the regular ball bearings. The big spring clip looks like it’s from a synchro unit, and the baulk ring looks awful. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 16, 2022 Author Share Posted January 16, 2022 I found a longer Allen key (3/16) and the six cap heads are out. I read @Snaggerthat you replaced some with longer and tapped them to drift the bearing out of the rear cover. However there are threads in my cover so not a clearance for the bolts (screws). I presume I have to clear them with a drill bit so that I can get into the bearing carrier? I don’t have any longer ones with that thread anyway so am at a stop. Also the main shaft (sun shaft?) has a couple of bad teeth but maybe that’s ok Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 16, 2022 Author Share Posted January 16, 2022 I haven’t a clue about the washer or the spring ring that’s broken. I can see the curled end of the rest of the spring in the rear gear set. I also can’t release the circlip in there as it’s too tight. Maybe once the shaft has been drifted out I can attack it if needed. Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 16, 2022 Share Posted January 16, 2022 If that’s the worst of the sun gear damage, I think it’s ok. Dress the damage to make sure any protrusions are removed. The rear housing and sun shaft look the same as the Series version. It’d be good for their own costs to rationalise as much as possible. I don’t remember if I drilled the threads for those six retaining bolts in the casing, but it’d do the trick. Certainly, those are the bolts I replaced with longer substitutes to drift the bearing retainer out as it is an interference fit in the casing and that is the most likely damaged bearing and appears to be the source of the noise. That bearing is the most susceptible to oil starvation, which is what damaged mine. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 16, 2022 Author Share Posted January 16, 2022 Thanks for that. With me it's all about confidence. I'd hate to muck it up. I will need to find some longer bolts then - Sheffield should have some somewhere! Thanks again. 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 16, 2022 Share Posted January 16, 2022 I’m trying to work out what the broken parts are. The spring clip is from the synchro unit - it holds the three slippers in place and is what gives the “hold” in the selected positions on the synchro. I think they used a Series synchro on the Series overdrive to simplify spares, and that had a different detent system in the synchro unit, but I may be remembering incorrectly. The broken washer looks like a thrust bearing race or a shim, and by the thickness, I’d suggest the latter. Mine doesn’t have any shims for the planet gears in their carrier, but from the location of the broken shim before you removed it all, that looks like a possible source. Can you see any shims on the other planet gears? The oil looks very grey and there is a surprising amount of rust. I think your LT230, or maybe this unit, has a water ingress issue that may well have contributed to the bearing failure. The balk ring failure and wear looks like it could be a mix of poor quality parts (baulk rings should not have steel cores, I believe, and definitely don’t on Series boxes) and the selector rod problem that could have caused pressure to be applied continuously to the ring, but that is unlikely as the detente on the synchro hub and the selector shaft with the fork should have provided a counter force that would require a significant load on the lever and connecting rod to press the baulk ring against its cone. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 16, 2022 Author Share Posted January 16, 2022 I am in touch with Ray at Global Roamer. He has asked for photos once it's in bits so I will report back but with the time difference I doubt I will hear until overnight Monday / Tuesday at the earliest and that assumes I can remove the rear cover on Monday. I'm still trying to fathom out exactly how it works! I know that input / output are concentric and somehow the output is engaged through the planet gears but with the reduction gearing coming in when selected. I can't yet work it out. The only drawing I have is the cross section engineering / parts diagram and it's not possible (for me) to work it out. Do you have any photos from your overhaul? I haven't looked on your website for a while... Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 16, 2022 Share Posted January 16, 2022 Ray is very helpful. He gave me plenty of advice on how to strip the unit as some of it isn’t obvious. He did say it wasn’t designed to be stripped, so he didn’t know how manageable it’d be. Those six bolts removing the rear bearing retainer was an effort but not complex. It was stripping the planet gear carrier to replace the bearings in that which was so hard - I needed to replace the skewed sun gear bearing in its centre and check the bore, and it wouldn’t get past the planet gears as their teeth overlapped the bearing, but the bolts to separate the carrier halves were on the wrong side so the carrier had to be separated from the ring gear back plate first! To do that required the removal of a large circlip which was accessible only through a narrow gap between the carrier and another body. Once that was out, which was the worst part of the whole job, it became a lot simpler. That circlip needed a large circlip plier modified to be bent to clear the components. It took me a couple of hours to get the thing out, even with that modified tool. Epicyclic gears work in an orbital manner, hence the names sun and planet gears. The input shaft from the gear box goes to the planet gear carrier. The output shaft is outside of the input shaft and is attached to the ring gear that engages on and surrounds the planet gears. The sun gear and shaft are not connected directly to either. The gears are all continually in mesh. When the overdrive is disengaged, the synchro hub slides to lock the planet gear carrier and ring gear carrier together with the ring carrier dog teeth and input shaft splines. No real force is transmitted through the gears as it is carried through the synchro ring to the ring dog teeth directly. The sun gear shaft is not really doing anything and will spin at the same rpm as the ring gear and planet carrier assembly because the planet gears are not turning on their own axles at all - the whole lot is essentially acting as one rotating mass. When you select neutral, the synchro ring slides aft, moving off the ring carrier dog teeth so the two carriers can rotate independently. This differential motion between the carriers would cause the planet gears to rotate on their own axles as they roll around the inside of the ring gear. When you select engaged, the synchro slides further aft and locks the sun shaft to the casing using the shaft splines and the rear bearing retainer’s dog teeth. If the sun gear is now fixed, as the carrier is rotated around the sun by the gear box, the planet gears have to roll around the sun gear as they orbit. Think of the Earth spinning as it orbits the sun. Their rotation forces the ring gear to rotate faster than the planet gear carrier. Automatic gear boxes use the same principle by locking different parts to cause planet gears to increase or decrease drive ratios, using hydraulic pressure on multilayered clutch packs with splines on the inside diameter of some laters and the outside of the other layers to lock the planet carrier to the ring or the sun shaft or the ring to the casing. Clever and compact, and once gearset gives three selectable ratios depending on which “onion layer” is locked. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 16, 2022 Author Share Posted January 16, 2022 Excellent, thanks very much. I will read and look at the same time. Yes I can see that circlip and the tiny gap that the pliers need to pass through - arghhh. Now, if you are back at base, you need to go to sleep! Thanks again Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 16, 2022 Share Posted January 16, 2022 Not to worry, I’m not at base. Stuck in Frankfurt for three days on a cargo trip, and we aren’t allowed out of the hotel. Reserve month, so no roster, just told at 6pm what I’m doing the next day. I got put onto “standby” for yesterday, where we are available for immediate calls if someone goes sick, but mine was special - it was “high quality standby”, whatever the hell that is, then I got this flight but they didn’t call me; I just got the SMS to say the car was waiting outside to take me to work! Err, what? 1 1 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 17, 2022 Author Share Posted January 17, 2022 I have made some progress but on the easy end which I will show. However @Snagger, on the subject of impossible to access circlips, which one is the one to remove? Is it the one in the first photo or one of the two inside the gap between input and output? After washing it’s clear that the planet bearings are no good so I need to open it fully. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 17, 2022 Author Share Posted January 17, 2022 I wandered into Mister Gearbox in Sheffield (https://mistergearbox.co.uk) looking for help. Amazingly, early on a Monday morning, the boss there helped clean and then worked on the unit. The rear housing went into a 55C pressure washer and then the rear shaft and bearing came out with gentle taps, using longer 1/4” UNF screws. The boss even fettled the sun shaft at those slightly damaged teeth 4 Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 18, 2022 Share Posted January 18, 2022 Good workshop! Aluminium expands more than steel with heat, so that would explain the relative ease of removing the sun gear after washing. The swine circlip that is the one you need to remove is the one below the planet carrier in the first photo of your last post. Good luck! Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2022 Author Share Posted January 18, 2022 I have fully dismantled it with the moment of success at the circlip coinciding with Emma R's winning shot at the Australia Tennis Open first round. It's mainly bad news though. 3 hours ago, Snagger said: The swine circlip that is the one you need to remove is the one below the planet carrier in the first photo of your last post Did you mean the last photo in the first post? That is the one needed to release the input shaft and planet gear carrier from the output shaft and it is accessed 80mm down the gap between the two here: Not this one which retains the big bearing, which I removed afterwards... Once the deep down circlip was out, it needed just a mild press to push the input shaft down and out to separate it from the output part. My poor circlip pliers will never be the same again. Then the planet carrier screws, fairly tight with threadlock, were released and the carrier very carefully drifted apart to allow access to the gears and bearings... Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2022 Author Share Posted January 18, 2022 Now the bad news started as I lifted the planet carrier apart to see a horrible sight. I lifted the first planet gear and the needles fell out. I wasn't expecting this. Needle bearings are always 'caged' aren't they? The next one looked better but they are still all loose, however the last one looked like this as I lifted the gear away... One of the planet shafts is so worn that you could trip up on it. So I am amazed that it was even working and very sad that it is in such a mess, after only a few thousand miles in my ownership. Ray at the Global Roamer Corp. is still returning emails but is on holiday until later in the week. I will need to see what he says... 1 Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted January 18, 2022 Share Posted January 18, 2022 50 minutes ago, Peaklander said: Needle bearings are always 'caged' aren't they? Unfortunately not, think landrover prop shaft joints, unimog steering regards Stephen Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2022 Author Share Posted January 18, 2022 Ah yes - of course. So in this case is the correct quality added individually, with the gear sitting on the shaft? Their drawing suggests this and there would be 40 in each Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 19, 2022 Share Posted January 19, 2022 19 hours ago, Stellaghost said: Unfortunately not, think landrover prop shaft joints, unimog steering regards Stephen Motorbike headstocks, some chainsaw drive sprockets... Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 19, 2022 Author Share Posted January 19, 2022 20 hours ago, Peaklander said: is the correct quality added individually, Do you literally add the individual rollers one by one? These gears seem to have them double stacked which would make it very difficult... Quote Link to comment Share on other sites More sharing options...
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