Maverik Posted November 11, 2009 Share Posted November 11, 2009 I have a lot on my to do list so here is my next big job: Gearbox, transfer box replacement. I have a LT77 (first model 'D') Gear box and standard trans box T230 (1.667)I was thinking of upgrading the gear box to a short bell housing R380 and changing the transfer box to one of a ratio to 1.222 I need ultimate reliability in my machine and I can't guarantee what the fitted ones are like, or how they've been treated in the past, going by what I've found so on the landy... I'm expecting the worst. I found a wee formula on Ashcrofts website showing the difference in MPH per 1000rpm for the different ratio's of trans boxes - hence how I have come to the conclusion of dropping to the 1.222 ratio. Can anyone see any problems with me up rating the transfer box ratio. The driver unit is a re-con Disco 200TDi so plenty of pull. What kind of set ups to people have on 200 Tdi??? Bearing in mind this is a expedition vehicle that I intend on driving across North Africa and down into Saudi next year. Cheers Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted November 11, 2009 Share Posted November 11, 2009 I have a defender 200tdi with a short R380 and a 1.22 LT230 from a Disco 2. It runs well and i'm happy with it. I've got 235/85/r16 tyres on as well. If anything its slightly high geared especially when towing but nothing dramatic. You will find that you spend more time in 4th than you did and when you get up to a decent speed you've got another gear left to use. And i just never get into 5th when towing anything heavy. Quote Link to comment Share on other sites More sharing options...
Guest wunntenn Posted November 11, 2009 Share Posted November 11, 2009 Mine's a 110 (previously with 2.5TD) now with a 200 TDi. Recently installed Ashcrofts LT77 gearbox and transfer box with 1.222 gearing, and to give me some flexibility to cope with the gearing change and generally make driving a bit more pleasurable (particularly going up hill!) installed a bigger intercooler and had the fuel pump tweaked, and a hybrid turbo (and on 235/85/16's). Its a reliable upgrade, makes the engine very flexible, oomph in 3rd is brilliant and cruising relaxedly at 55-60 is stress-free, with a good dose of poke left for walloping up to 70. As Jimmy N says, you'll be sat in 4th where previously you'd be in 5th and reaching for another gear. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 11, 2009 Share Posted November 11, 2009 If you are building an expedition truck as in the title, are you planning to go on expedition on motorways or in the bush? A 1.22 TXB might suit fir the drive across europe for a few days, but the rest of the journey - say 3 months might be better suited to a 1.4:1 defender box. Just a thought. Quote Link to comment Share on other sites More sharing options...
cabell Posted November 11, 2009 Share Posted November 11, 2009 I installed a 1.2 tcase behind a 200tdi in my 110 pickup. It's an '83 and has the original lt77 which I believe has a slightly lower 5th gear ratio that the later lt77s. I couldn't be happier, the truck is very comfortable at 65 mph. First gear in high box is a bit tall, but completely managable. I'm on 255/85s (33"). Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 12, 2009 Author Share Posted November 12, 2009 If you are building an expedition truck as in the title, are you planning to go on expedition on motorways or in the bush? A 1.22 TXB might suit fir the drive across europe for a few days, but the rest of the journey - say 3 months might be better suited to a 1.4:1 defender box. Just a thought. One of the issue's is yeah I will be driving across Europe, but then have a bit of a desert to cross and then some... I do intend on using this truck for long distance rough stuff, I had wndered about wether going to 1.222 was a little to high. The vehicle will be loaded for the majority of the time. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 12, 2009 Share Posted November 12, 2009 Assuming your truck is a 110, the tyres are bigger as standard (235/85R16) than a Disco or RR (205's) so there is a gain in gearing there. Also, you will be loaded up a lot of the time and not as aerodynamic, especially if you have stuff on the roof. Look up the gear ratio calculator spreadsheet in the tech archive, it includes tyre sizes and allows you to compare various combinations side-by-side. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 12, 2009 Share Posted November 12, 2009 One of the issue's is yeah I will be driving across Europe, but then have a bit of a desert to cross and then some... I do intend on using this truck for long distance rough stuff, I had wndered about wether going to 1.222 was a little to high. The vehicle will be loaded for the majority of the time. Do what FridgeFreezer suggests, but i would think you may be better off going for the 1.4:1 defender box personally - especially given where you will spend most of your time. You're not really talking about 4 months cruising around at 80mph, probably closer to 35/40 on average, so the 1.4 might be a better bet IMO. Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 12, 2009 Author Share Posted November 12, 2009 Do what FridgeFreezer suggests, but i would think you may be better off going for the 1.4:1 defender box personally - especially given where you will spend most of your time. You're not really talking about 4 months cruising around at 80mph, probably closer to 35/40 on average, so the 1.4 might be a better bet IMO. Is it even possible to get a defender up to 80mph... and keep it there for any length of time? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted November 12, 2009 Share Posted November 12, 2009 On a good metalled road, yes of course. On dirt tracks, I think probably not. Not if you wanted to still be in one piece after five minutes. I would advise against 1.2 for loaded travel. A friend of mine has a 110 with a 1.2 transfer box and it's noticable when towing or loaded. Quote Link to comment Share on other sites More sharing options...
Eightpot Posted November 13, 2009 Share Posted November 13, 2009 You shouldn't have any problems with that gearing if you keep the weight reasonable, I've been running a 1.22 'box and 235's for a while now. Sand crossings were the only place I noticed the gearing being anything less than perfect, though 50% of that lies with the TDi engine not being that gutsy on sand anyway. probably another 25% of that is down to tyres as well - MT tyres can tend to bite into the sand rather than float on it and causes more drag. I did at times find myself wanting fourth gear a little lower geared, but overall I wouldn't swap it. If you have a good engine and have tweaked the pump a bit to give you a bit more poke this will help. Quote Link to comment Share on other sites More sharing options...
biodoctor Posted November 15, 2009 Share Posted November 15, 2009 I've got a defender 90 with a 200tdi ,i recently changed the transfer box to one out of a disco ,best mod i've done !!! Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted November 15, 2009 Share Posted November 15, 2009 Is it even possible to get a defender up to 80mph... and keep it there for any length of time? I think you'll find with Defender handling that 3 lanes isn't wide enough to achieve this Mo Quote Link to comment Share on other sites More sharing options...
jbs Posted November 16, 2009 Share Posted November 16, 2009 Is it even possible to get a defender up to 80mph... and keep it there for any length of time? Yes it is as mine will do this-i too have the disco T-Box and i have reconditioned injectors and a recon pump too,with a full width intercooler on 7.50x 16 SAGS on my 90 Quote Link to comment Share on other sites More sharing options...
kkk2 Posted November 16, 2009 Share Posted November 16, 2009 I have recently fitted a new gearbox to my truck (1989 110), its a Lt77s which has the same ratio as the r380, while it was reconned I got a cooling modification fitted to it as well. I have a small radiator under the wing, For long haul stuff this keeps the gearbox cool. This facility is also available on the R380 gearbox too, however the shortshaft R380 is an expensive conversion. As for Xfer box, all transfer boxes have same lower ratios, so offroad there is no differance. On road we have both defenders with 1.2 and 1.4 Xfer boxes, the 1.2 runs quiter on road but like a naturally aspirated will find the hills before you see them when towing. I believe the 1.4 gives a better allround performance. K Quote Link to comment Share on other sites More sharing options...
Aragorn Posted November 16, 2009 Share Posted November 16, 2009 Last time we were down sarf in the A4 we were sat on the A14 with the cruise control on at 75ish and a 110 military defender passed us doing easily 85. He kept it up too and after a few minutes was waaay in the distance. We caught up with him on a few uphill stretches, but once over the crest he was off again! So yes, a defender can sit at over 80 for a prolonged period wihtout much trouble, just dont show it a hill Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted November 17, 2009 Share Posted November 17, 2009 I have recently fitted a new gearbox to my truck (1989 110), its a Lt77s which has the same ratio as the r380, while it was reconned I got a cooling modification fitted to it as well. I have a small radiator under the wing, For long haul stuff this keeps the gearbox cool. This facility is also available on the R380 gearbox too, however the shortshaft R380 is an expensive conversion. As for Xfer box, all transfer boxes have same lower ratios, so offroad there is no differance. On road we have both defenders with 1.2 and 1.4 Xfer boxes, the 1.2 runs quiter on road but like a naturally aspirated will find the hills before you see them when towing. I believe the 1.4 gives a better allround performance. K The 'thermostat housing' as landrover call it ... the adapter bit that the pipes go in to on the gearbox for the gearbox oil cooler can't be fitted on a 200tdi with a short R380 unless you modify the transmission tunnel. Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 17, 2009 Author Share Posted November 17, 2009 The 'thermostat housing' as landrover call it ... the adapter bit that the pipes go in to on the gearbox for the gearbox oil cooler can't be fitted on a 200tdi with a short R380 unless you modify the transmission tunnel. How much of a modification do you need to do? one of the main drivers for getting a short R380 was the ability to install the cooler. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 17, 2009 Share Posted November 17, 2009 I've mentioned this before, but i do wonder if its possible to put a deeper sump on the transfer box like the ones from Rocky Mountain - that has extra cooling fins to transfer heat from the transmisson that way. BUT in addition, you could quite cheaply install a pump and thermostat housing in that sump that runs to a cooler - the pump comes on when the thermostat reaches a set temp, circulates to the cooler and cools the transmission this way - there must be some benefit to the main box in this way. EP90 may be too thick for this i suppose, but other than that it might work?? Cheaper than an upgrade from LT77 to R380 as well. Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted November 17, 2009 Share Posted November 17, 2009 How much of a modification do you need to do? one of the main drivers for getting a short R380 was the ability to install the cooler. The adapter bit for the R380 sits on the passenger side luckily. I'd say it's only about 25mm but the problem is that its the seat box that needs cut away and then the tunnel modified. Its do-able but its one of then things i was going to do but never bothered getting round to it. Still worth the change to R380 though. Quote Link to comment Share on other sites More sharing options...
kkk2 Posted November 17, 2009 Share Posted November 17, 2009 I had to mod the Lt77s with the cooler the same way, easily done, I did it after fitting the gearbox, as there was vibration where the cooler was rubbing off the seat box, If this is all the mod needed then its not even worth worrying about, The cooler is good and works well today after a 120k run with a heavy trailer the gearbox was cool enough to touch. I would also consider a fully synthetic oil for the box which I will do when I do the first oil change at about 1000 Km after fitting K Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 17, 2009 Share Posted November 17, 2009 Switching to the 1.2 t. case seems to really lower the gearbox temps as it is running slower. Quote Link to comment Share on other sites More sharing options...
kkk2 Posted November 17, 2009 Share Posted November 17, 2009 Switching to the 1.2 t. case seems to really lower the gearbox temps as it is running slower. Yep have that done as well Quote Link to comment Share on other sites More sharing options...
western Posted November 17, 2009 Share Posted November 17, 2009 The adapter bit for the R380 sits on the passenger side luckily. I'd say it's only about 25mm but the problem is that its the seat box that needs cut away and then the tunnel modified. Its do-able but its one of then things i was going to do but never bothered getting round to it. Still worth the change to R380 though. just checked the 110 parts book, there is no mention on the gearbox tunnel & seatbox page about different parts for vehicles fitted with gearbox oil cooler adaptors, those vehicles without a oil cooler fited still have a blanked off adaptor on the gearbox, that can be made or swapped for a drilled/threaded version to allow fitting of the gearbox oil temp switch, this sits in the same place as the oil cooler hose adaptor. Quote Link to comment Share on other sites More sharing options...
jbs Posted November 19, 2009 Share Posted November 19, 2009 Ralph could you put up a pic/diagram as to where it is on the Lt77 box please? as I'm sure I'm not the only one who's curious as to where it is on there. TIA John Quote Link to comment Share on other sites More sharing options...
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