reb78 Posted October 21, 2018 Share Posted October 21, 2018 (edited) As above. Should an LT77 (G suffix box) cope with lots of motorway work? I travel from Cornwall to London and back each week. Thats 500miles of motorway plus local travel every week. My layshaft bearings have gone for the second time in two years. This set have covered only 30,000 miles. As many know, I run a GKN overdrive so engine and main box revs are significantly reduced such that even at 80 I am revving lower than the same vehicle without an overdrive at 70. I sometimes tow but not that frequently. Do I have the wrong box for my application or is there potentially something more wrong with the box itself? Engine and gearbox levels are checked weekly. Diffs etc every 6000 miles at service time (so every 3 months at my current mileage). I’ve spoken to a few of you about this in person but wondered on the wider thoughts. Edited October 21, 2018 by reb78 Quote Link to comment Share on other sites More sharing options...
cackshifter Posted October 21, 2018 Share Posted October 21, 2018 It's true the revs are less but with an overdrive the input torque and therefore bearing load will be correspondingly greater - assuming the same power is needed to propel you and surrounding hardware at the same speed. I'd wonder if you are using the best oil for this? There isn't much else you have influence over. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted October 21, 2018 Share Posted October 21, 2018 The gearbox in 45 was second hand when I put it in. It's done Ladoga including driving there and back, lots of off roading, a fair amount of towing and I'm not shy with the loud pedal. It's covered about 50k and been in use daily for 10 years since I put it in. I'd say you have a problem especially if the bearings were in the same box. If it was two different boxes perhaps the overdrive is starving it of oil somehow. Mike Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 21, 2018 Author Share Posted October 21, 2018 13 minutes ago, miketomcat said: The gearbox in 45 was second hand when I put it in. It's done Ladoga including driving there and back, lots of off roading, a fair amount of towing and I'm not shy with the loud pedal. It's covered about 50k and been in use daily for 10 years since I put it in. I'd say you have a problem especially if the bearings were in the same box. If it was two different boxes perhaps the overdrive is starving it of oil somehow. Mike Same box Mike. Bearings were replaced 30k miles ago. They’d done 66k miles before that (the box has had a heap of issues - once its off the same one is not going back in) How would the OD starve the main box of oil? They are all seperate. Oil - using ATF III at the moment. Have tried MTF and difflock but settled on ATF and regular changes. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted October 21, 2018 Share Posted October 21, 2018 Mine seems okay doing c. 700 miles a week, including a fair chunk of motorways. I don’t cruise at 80 though, or even 70! I did have the original box (I think) fail last year, the bearings got noisy. But I don’t think motorways could cause it, unless you’re overheating the box perhaps? But they worked fine in Discos knocking about the motorways for years. Quote Link to comment Share on other sites More sharing options...
Eightpot Posted October 21, 2018 Share Posted October 21, 2018 Only broke my first LT77 last year, in a very heavy 110 that did lots of very long distance hot climate work with plenty of sand driving. The cause of the layshaft breakage appears to be because I forgot to put any oil in 🙃 Done lots of very long distance work with other lt77s, no probs at all. It might just be your last repair wasn't 100% or the bearing was lower quality?? Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 21, 2018 Author Share Posted October 21, 2018 The person who repaired it said they used Timken bearings. They also admitted to using inferior bearings in the original build so I was hoping that Timken parts would get me more than the 66k it took the first ones to fail! But alas no! This is whats making me question the box or the setup. At the risk of advertising this ad further, is this worth a shot? https://www.ebay.co.uk/itm/Land-rover-defender-lt77-gearbox-suffix-H-90-110-military-spec/153225783380?hash=item23acf7e854:g:iUgAAOSwdmlbyyTe its probably recon rather than new isnt it? Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 21, 2018 Share Posted October 21, 2018 If the same workshop did both rebuilds, the problem may be with them, not the bearings. It's possible you have damaged casings or shafts that are causing misalignment. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted October 21, 2018 Share Posted October 21, 2018 I didn't know whether the overdrive shared gearbox oil like my pto does. If it were mine I'd either purchase that one on eBay though it does seem pricey or get an Ashcroft re-con. At least an Ashcroft will have some come back. Mike Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 21, 2018 Share Posted October 21, 2018 Er ^^^^^^^^^^^^ Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 21, 2018 Share Posted October 21, 2018 Mike, get some sleep, there's an LT230 in the way you idiot Ref the original question; bearings can wear out due to wear or bearings can wear out due to misalignment / preload / lubrication / debris / etc. so I'm voting your box has other problems. You don't say which lump you have, big lumpy diesels can kill boxes especially if you're labouring the box in a higher gear than it would otherwise be, but if you're on (I'm assuming) a stock 200TDi it should be within its happy limits. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 22, 2018 Author Share Posted October 22, 2018 (edited) Yup. A 200tdi Fridge, so its not like its mated to a Cummins or GM V8 monster. A few folks have mentioned misalignment or potential mismatching of case parts as a potential cause. For this reason I am going to ditch this box and need to make a break away from it. This will be the fidty time in ten years this box has had to come off for a problem - second time for the layshaft bearings. Cant keep on like this! Edited October 22, 2018 by reb78 Quote Link to comment Share on other sites More sharing options...
cackshifter Posted October 22, 2018 Share Posted October 22, 2018 You 'could' contemplate a R380/stumpy conversion a la western - then you could go for the R380 bearing upgrades, though western hasn't reported much trouble and he does galactic mileage. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 22, 2018 Author Share Posted October 22, 2018 Ive been considering the R380, but its a fair bit more to spend including the bearing upgrades and if the LT77 is suitable for what I need, i really dont mind the box. Its a bit of a dilemma though. I enquired at Syncro Gearboxes about the stumpy R380 but they arent taking orders until after christmas because of workload. Quote Link to comment Share on other sites More sharing options...
Arjan Posted October 22, 2018 Share Posted October 22, 2018 We have the LT77 in several vehicles that covered many more miles that you describe and never had problems. The obvious thing is to do is using the best quality oil you can afford. We change oil in the boxes & diffs every 20k miles (engines 10k miles) and they are still going strong. The one box we had to change was the Series one after 150k miles, 30 years of abuse, submerging and all the other sh.. we could get ourselves into... I'd seriously consider another source for your transferbox readings about your problems.. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 22, 2018 Author Share Posted October 22, 2018 Thanks Arjan. Yes, its certainly time to break away from the current company - one problem could just be bad luck but the list is quite long now though. Trouble is it means taking a financial hit as I am not comfortable using the box I have for exchange so I need to purchase outright. In my opinion, the current box is not fit for exchange (given discussions with others and the comments on here) and were I to exchange elsewhere I would potentially be passing a problem to someone else. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 22, 2018 Author Share Posted October 22, 2018 Just a correction to the first post - I dont think it makes any difference, but the current box is an H suffix, not G. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted October 22, 2018 Share Posted October 22, 2018 My G suffix box is at 27 years without any bearing failures. Something must not be quite right with your box or the oil you use. Did an 8000 km trip this summer. Still shifts like new. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted October 22, 2018 Share Posted October 22, 2018 1 hour ago, reb78 said: Just a correction to the first post - I dont think it makes any difference, but the current box is an H suffix, not G. May I ask who built the current one? Quote Link to comment Share on other sites More sharing options...
Arjan Posted October 22, 2018 Share Posted October 22, 2018 I get anything transmission from Synchro (Shabs) in Wales. Very happy with what I got so far - and a nice bloke to work with. He's very busy, but talking directly to him will probably help. In December, I'm collecting an R380 from him for another project. Driving over to Wales to collect it should tell you something. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 22, 2018 Author Share Posted October 22, 2018 Yup. Ive heard good things, but he’s not taking new orders until after new year. Its a long time to be without the car hence looking at other options like the one on ebay. Quote Link to comment Share on other sites More sharing options...
Arjan Posted October 22, 2018 Share Posted October 22, 2018 As I said, he's busy.. I will not comment on other suppliers - esp. a well known one. Ebay is a gamble... Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 23, 2018 Share Posted October 23, 2018 I think ebay would be wasting your money. Not many companies do recon (of anything) right - to little re and too much con. They cut corners, reuse bad parts, use cheap pattern parts and don't bother setting up tolerances correctly. Anything on ebay would likely fall into that category. Spend a little more up front to save a lot in the long run. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 23, 2018 Author Share Posted October 23, 2018 I was lookomg at a spexific box though Snagger - see the link above - if its a true military recon that someone else has bought and is selling on would it be less ‘con’ and reasonable workmanship? I’d assume MOD wanted things done properly. The ratios are all quite different to the tdi box though, but I wonder if they could make the overdrive a nicer thing to use? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 23, 2018 Share Posted October 23, 2018 I wouldn't stress about returning your box as an exchange, I'm sure they get far far worse stuff in & part of the process is to check which bits can & can't be re-used / need machining. Quote Link to comment Share on other sites More sharing options...
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