Snagger Posted October 20, 2019 Share Posted October 20, 2019 How likely do you think it is that the brake cone you removed was the source of the trouble? Quote Link to comment Share on other sites More sharing options...
western Posted October 20, 2019 Author Share Posted October 20, 2019 Can't be 100 % sure but I didn't fancy taking it off again if I had left it fitted, there's just enough space for OD to be removed/fitted & for its size it's a heavy unit, Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 20, 2019 Share Posted October 20, 2019 When you are saying brake cone, do you mean the cone clutch or the brake ring? That clutch was brand new. Quote Link to comment Share on other sites More sharing options...
western Posted October 20, 2019 Author Share Posted October 20, 2019 1 hour ago, reb78 said: When you are saying brake cone, do you mean the cone clutch or the brake ring? That clutch was brand new. The cone with the friction material on. I know it was new as Neil & you told me. Done a fluid level top up, it needed about 30ml so it just runs out the fill/level hole. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 20, 2019 Share Posted October 20, 2019 Did Martin at D44 have any useful advice when you spoke to them? Quote Link to comment Share on other sites More sharing options...
western Posted October 20, 2019 Author Share Posted October 20, 2019 I didn't ring, just bought the seal kit & brake cone from Overdrive repairs in Sheffield & got on with the job. Quote Link to comment Share on other sites More sharing options...
western Posted October 24, 2019 Author Share Posted October 24, 2019 OD seems to be working OK, But when slowing/ stopping at traffic lights or waiting to turn at a junction the OD occasionally doesn't give drive straight away when wanting to move off, this in the disengaged position, which is a bit annoying, I'm thinking it's the friction material bedding in, as the cone should be held tight to the brake ring by the 4 springs. Once it grips drive through the OD is very good. Quote Link to comment Share on other sites More sharing options...
western Posted October 25, 2019 Author Share Posted October 25, 2019 Overdrive has worked well on the long drive up to Wiltshire today, didn't slip when engaged but still slips occasionally when disengaged, but seems to be getting better slowly. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted October 25, 2019 Share Posted October 25, 2019 If it’s improving, sounds like something bedding in then? Quote Link to comment Share on other sites More sharing options...
western Posted October 25, 2019 Author Share Posted October 25, 2019 I think so, when engaged it just worked fine, Quote Link to comment Share on other sites More sharing options...
western Posted October 27, 2019 Author Share Posted October 27, 2019 OD is working OK so far his weekend, been upto Swindon, then Telford, now on the way home, its doing well both disengaged & engaged, can truck along at 70 on motorway with no problem. Quote Link to comment Share on other sites More sharing options...
William Pearson Posted November 5, 2019 Share Posted November 5, 2019 Hi All, been following this thread with great interest. Anyone out there have a unit for sale? Either working or not! Keen to have a go at fixing one. Quote Link to comment Share on other sites More sharing options...
western Posted November 5, 2019 Author Share Posted November 5, 2019 There is or was one on Facebook marketplace, seller was wanting £850 for it. This is it https://www.facebook.com/marketplace/item/2208953192551571/ Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 10, 2019 Share Posted November 10, 2019 Hi all, I am the one who was writing the article at landypedia mentioned above. https://www.landypedia.de/index.php/Überholung_eines_GKN_Overdrives It was a hard peace of work reading all that stuff, but worth every line. Since I am not a specialist with GKN ODs, I do have problems with mine as well 🙂 My suggestion (and I am about that) is to measure the hydraulic pressure of the OD. In my eyes, it can be made at the screw, which sits beside the plate on the bottom. I think the hole will just go into the oil chanel of the solenoid. My experience with mine is, that it will disengage when it becomes hot. I made some experiments with oils. With ATF it disengages after about 25 km. Half ATF and half engine oil extend it up to 40 km. Only engine oil will make 50 km. Now I tried 75W90 gearbox oil ... and found it engaging quite reliable and long ... but it did not disengage anymore. Only if revs are really down. It seems to be very dependent on viscosity. Another problem seems to be disappearing oil. I put the vent hose into a catch tank, to see if it disappears here. I did not check yet, if it disappears into the LT230. I heard about it, but don't think so. Sigi 1 Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted November 11, 2019 Share Posted November 11, 2019 As the whole device is reliant on the clutch material getting grip and stopping the Overdrive from slipping, using the wrong type of oil will be very detrimental to it's performance. If the hydraulics and clutch areas were separated internally then you might be able to try different oils, but to deviate totally from the specification is only going to lead to the clutch / brake slipping internally. You should only be using ATF!!! Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 11, 2019 Share Posted November 11, 2019 You are absolutely right. This was just a test, to learn more about the hydraulic pressure. Results point to the necessity of measuring the pressure. Even it was absolutely the wrong oil (it is too slippery) there was no slipping. The fact, that it did not disengage reliably may point to the solenoid valve, which got stuck with the high viscosity. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 11, 2019 Share Posted November 11, 2019 2 hours ago, Sigi_H said: You are absolutely right. This was just a test, to learn more about the hydraulic pressure. Results point to the necessity of measuring the pressure. Even it was absolutely the wrong oil (it is too slippery) there was no slipping. The fact, that it did not disengage reliably may point to the solenoid valve, which got stuck with the high viscosity. Thats what it is IMO. The seals between the transferbox and the overdrive dont last forever. The dissapearing oil you refer to above is transfer from one to the other. Eventually the OD sucks oil from the transferbox and when it is over-full and has EP90 in it, it does two things - spits it out of the breather hole and doesnt disengage properly. Mine needs the seals doing currently. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 11, 2019 Share Posted November 11, 2019 That's plausible, but the OD was rebuilt 12,000 km ago. That's why I don't really believe it yet. Because there is often too little oil in the OD, it normally doesn't engage. The behaviour not to disengage is only possible with gear oil in it. That's why I really want to measure the pressure in order to see a pressure profile and see the reason for shifting or not shifting. I built a provisional catch tank from a PET bottle, to see if oil is coming from the breather. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 11, 2019 Share Posted November 11, 2019 I prepared all parts to measure the pressure. But I don't know the size of the thread of that screw on the bottom of the OD, in order to prepare an eye fitting and a banjo bolt for the steel braided hose I took. Does anybody know? Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 11, 2019 Share Posted November 11, 2019 7 hours ago, Sigi_H said: That's plausible, but the OD was rebuilt 12,000 km ago. That's why I don't really believe it yet. Because there is often too little oil in the OD, it normally doesn't engage. The behaviour not to disengage is only possible with gear oil in it. That's why I really want to measure the pressure in order to see a pressure profile and see the reason for shifting or not shifting. I built a provisional catch tank from a PET bottle, to see if oil is coming from the breather. Do you check the transfer box oil when you check the OD? If you get the levels in the transferbox and OD correct, then check again after using them both, if the transfer box is overflowing from the filler hole, I think that gives you an answer? Otherwise, unless there is an external leak (which I am sure you will notice) there is nowhere else for the oil to go. Unless its overfilled, the OD wont chuck oil out of the breather in my experience. Mine has been losing oil to the transferbox recently - its minimal and because of time I just top it up, but the other week, the OD was overflowing as it seems to have started drawing oil from the transferbox. I will take it all off over Christmas and replace the two face:face seals and the orange sealed bearing and it should all be fine again for another 100k miles. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 12, 2019 Share Posted November 12, 2019 (edited) 14 hours ago, reb78 said: Do you check the transfer box oil when you check the OD? If you get the levels in the transferbox and OD correct, then check again after using them both, if the transfer box is overflowing from the filler hole, I think that gives you an answer? Otherwise, unless there is an external leak (which I am sure you will notice) there is nowhere else for the oil to go. Unless its overfilled, the OD wont chuck oil out of the breather in my experience. Mine has been losing oil to the transferbox recently - its minimal and because of time I just top it up, but the other week, the OD was overflowing as it seems to have started drawing oil from the transferbox. I will take it all off over Christmas and replace the two face:face seals and the orange sealed bearing and it should all be fine again for another 100k miles. I didn't check the transfer box yet. That will be the next step on the weekend. When I was rebuilding the OD, I did not take the orange sealed NTN bearing. As this is a known weak point, it's also possible. I think I will put a catch tank to the breather of the LT230 as well. Put to the right level, this can prevent severe overfilling. Edited November 12, 2019 by Sigi_H Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 12, 2019 Share Posted November 12, 2019 I think the orange bearing is your likely issue then. They can leak. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 12, 2019 Share Posted November 12, 2019 I am afraid, it is so ... Quote Link to comment Share on other sites More sharing options...
western Posted November 13, 2019 Author Share Posted November 13, 2019 My unit is still occasionally slipping disengaged, 5 times on the way home from work this evening it wouldn't take up drive without some slippage, it did get slightly less slipping as it warmed up, but I can't rely on it to reliable & not slip - for example coming up to traffic light then being able to move straight away when the light change to green or when moving out of a junction, the OD slips then decides to drive, It's as if the 4 springs [although they are new] are not strong enough to keep the brake cone tight to the fixed brake ring, it does seem to be fine when engaged, as it was OK when I went up to the Telford area a few weeks ago, last fluid change was just under 950 miles ago. I am seriously thinking about removing it this weekend & refitting the normal transfer box gear, & just leave the OD in the garage or see if Devon4x4 want to buy the 2 units I have for spares. I've spent lots of time trying to cure this fault, it's had new springs,big filter, small filter cleaned, rear body cleaned so it was spotless, oilways cleared & clean, set of seals & brake cone, another solenoid with new seals but the fault still persists. having the OD not operating as it shouldis just so darn annoying & as it can't be relied on to give instant drive when disengaged it's close to being a driving hazard. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 13, 2019 Share Posted November 13, 2019 Put the springs from your original OD on this one as yours wasnt slipping? Quote Link to comment Share on other sites More sharing options...
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