CJRH Posted November 29, 2008 Share Posted November 29, 2008 I’ve decided to fit an LT77 gearbox with the 200TDI conversion in my 2a rather than a series gearbox. I know from using the search function that you need an LT77 with a LT230 transfer box, what I can’t find out is what ratio diffs I should use with this setup. I’ve already swapped them for 3.5 ones, is this correct? Also, with the LT77 gearbox, is it a lot longer than the series gearbox? Will I have to move the engine and gearbox mounts forward? Cheers, Chris Quote Link to comment Share on other sites More sharing options...
DaveSIIA Posted November 29, 2008 Share Posted November 29, 2008 90's/110's & Defenders all use 3.54 diff's. A SWB IIA should work ok with a 1.2 high ratio and a LWB with a 1.4 on 3.54 diff's. Much depends on your chosen tyre size as well. The LT77/LT230 combination is (IIRC) ~4" longer than the Series boxes. The distance between F & R propshaft flanges is different to a Series. You are into custom propshafts. Also check clearance behind the transfer box to the crossmember under the seat base if fitting to a SWB. Others have done the conversion and you might find a write up on this forum. Quote Link to comment Share on other sites More sharing options...
crazyfarmerboy Posted December 10, 2008 Share Posted December 10, 2008 you can also look at the ratio comparrision on ashcroft. they have a comparision table Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted December 10, 2008 Share Posted December 10, 2008 Or you can download the ratio comparison spreadsheet that is in the tech archive. As has been said, much depends on tyre sizes - you could run 4.7:1 Series diffs and a 1:1 LT230 to get a very low low range off-road whilst giving good on-road gearing, or run 3.54:1 coiler diffs with your choice of high range (1.2, 1.4, 1.6) which would give you the same gearing as a coiler. If the combo is going into an 88" it could be a bit tight, although removing the radiator cowling & engine fan gains a fair bit of space to shift the whole lot forwards. Quote Link to comment Share on other sites More sharing options...
Jon White Posted December 11, 2008 Share Posted December 11, 2008 200tdi will bolt into an 88" using the standard series engine mounts. You need a defender Lt77 NOT a discovery one. Ratios you need to work out as it also depends on tyre sizes. I'm running 1.22 transfer box with 4.75 diffs and 33" tyres. Jon Quote Link to comment Share on other sites More sharing options...
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