transfer box gear ratios

[v8seriesone]

i've got a 1994 300tdi 90 and cruising speed is a little low compared to, say, a discovery with the same engine and gearbox. I'd like to up the gearing in high ratio without affecting low ratio. Is it possible to swap the cogs in the transfer box for discovery items (are they a different ratio?) or maybe swap the whole transfer box? I'd like to make it more comfortable and economical on long journeys without affecting the off-road capability of the low ratios at all.

Any thoughts?

[bigfatsi]

I think SOP is to just swap em over. Other than the internals I believe they are exactly the same and should be a relatively easy procedure. I have, however heard warnings that if you are using large tyres you are running the risk of over-gearing it and struggling to get into top. I guess if you want both big tyres and a disco transfer box you could also think about tweaking for power too.

HTH

Simon.

[extreme90]

what tyres are you running ? this will be the dictator

low range is stock through out the lt230 range  
dan

[v8seriesone]

currently running 215 (or was it 225?) / 75 / 16
same diameter as 205s I think

but i will shortly be upgrading to 235/85/16s

[extreme90]

if you go upto that size your gonna struggle to pull with a 1.222 box in
you better off sticking with the 1.410 box and fitting some 33 inch tyres IMO
my 90 on std gearing and runs 33inch road tyres and cruises at 70 ish and pulls right upto a ton

altho it does have a full width intercooler and everything opend up

dan

[Litch]

Been running my 90 (unmodified 300TDi) with a Disco box & 265/75x16's for neraly 3-years now and I find it perfect on motorways, commuting, towing, hills, headwinds etc. I couldn't go back to the standard gearing as it seems just so low.