Transfer Box Ratio

[BigSi]

What’s your views on an LT230 transfer box with a gear ratio of 1.192?
What’s it good and, and what’s it bad at?

[L90OOK]

Very High geared.  You be hard pushed to use 5th gear...especially if you are running larger tyres too. IIRC Disco's are 1.22:1 ratio in the high range & this is what the defenders ones are changed for if you want a better motorway cruising vehicle...less rpm's.

[BigSi]

265/75R 16 Tyres, and not much call for 5th gear!!!

So better for low speed off-roading, but not so good for road use?

[L90OOK]

I'd imagine the low box ratio is the same as in all T/box's.  You may have probs pulling away in High Ratio (depending on your engine).
The engine will have to work harder to turn the wheels in High Range.  
What are you trying to achieve?

[BigSi]

Not sure, just wanted to get a low down of the gearing. Was hoping to get a little more ‘top end’ road speed, but still like the idea of the low gearing for off road use. Oh, and is a 3.5 V8.

[L90OOK]

Hmm, you'd probably be better off with a disco transfer box.  Higher than a defenders on high range & same low range gearing.
The 3.5 V8 may struggle with anything higher.

[BigSi]

Any suggested type or ratio?

[L90OOK]

1.211:1 std disco box...as long as you are not planning on changing the tyre sizes?

[ChrisV8]

That transfer box is out of a RR so will probably not have the bigger bearings of the later Disco one. Low range will be the same, have a look on Ashcrofts site they list all the ratios by transfer box number.

[Eightpot]

Had the ratio changed to 1.22:1 in my Tbox - only a matter of swapping a few cogs over.  No probs at all with gearing and i've only got a 200Tdi engine - a V8 will be absolutley fine.  
Mine is ex MOD though and my 1st and 2nd gears are a little lower which I guess helps, but nonetheless I never feel like the gears are too tall - wouldn't even mind it a little higher on the motorway.
Took it up the autobahn once, had it reading (an optomistic) 95!   :o

[BigSi]

Does somebody do a DIY re-gear kit, or is it a case of fitting a whole new transfer box? If so, what year Discovery would be the best bet?  :-k  :-k  :-k  :-k

[Eightpot]

I got my local land rover gearbox repairers (Whitehouse & son, Bobbington) to do mine, but I think Ashcrofts do a kit.

[smo]

Does somebody do a DIY re-gear kit, or is it a case of fitting a whole new transfer box? If so, what year Discovery would be the best bet?  :-k  :-k  :-k  :-k

Ashcrofts - however its not such an easy home fit but they can do it for you properly.

The 1.192 was somthing i had considered, i rekon its feasable with a decent ammount of power, but it doesnt change the low range box so is rarely found.

Best off sticking to a 1.22 disco box, or same ratio Q-gears for your current box. If you want low low low's, get an underdrive! Dont bother with an overdrive as they are pricey, unreliable (ish) and gain nothing over the 1.2 T box.

[Range Rover Blues]

I've got 235/85 on my RRC with the Borg-Warner box and I find the gears too tall, 1st if difficult to move off smoothly and 5th is a struggle in a headwind.  Try towing with it and it's awful.

It has a 3.9 EFi BTW.

[BigSi]

Been told by Dave at Ashcroft Transmissions, that I need a ratio of 1.410 (existing box geared too high).

It there a transfer box that has this as a standard ratio, or is it a case of getting the existing one re-geared with the new ratio?  :-k  :-k  :-k  :-k

[kourgath]

Hiya,

Hope this helps (and is accurate, I'm happy to be corrected by those with more understanding/knowledge)

I've got borg warner VC jobbie (1.206:1) in mine so I put 4.1:1 diffs in it. With 235/85R16s it does 25mph/1000 in 4th lockup (auto so about the same as your 5th). It used to be able to do 70 in second before lowering diffs.  Also diff change gave me back some engine braking lol!

1.411:1 was used in 110 4cyl petrol/ Naturally Asmatic Diesel (according to LR Experience Handbook which should give you a 13% reduction (Ashcroft website). As going from 205->235s gives an 11% increase this would be a good match.

The V8 on bigger tyres will need lowering if you intend keeping on-road performance brisk, as the smaller tyred RR/Disco wheels were approx 30inch, 235/85R16 are 32inch (or so) diameter, go to 35 and you'll need another 10% (ish) to keep the gearing the same.

Cheers
Gavin/kourgath

[kourgath]

Forgot this...

going from 3.54 diffs to 4.1 diffs gives a 13.65% drop in gearing.

I chose this route in the end as it gave me overall lower gearing for both on and off-road use.

Also with regard to the question about low range of LT230 transfer box, according the LR book all the low ranges were 3.320:1 it was only the high range that altered, the Borg-warner has a low of 3:244:1 so no major difference.

[smo]

Been told by Dave at Ashcroft Transmissions, that I need a ratio of 1.410 (existing box geared too high).

It there a transfer box that has this as a standard ratio, or is it a case of getting the existing one re-geared with the new ratio?  :-k  :-k  :-k  :-k

1.4 is a standard ratio for 99% of defenders - are you sure this was the advice from Dave?

[kourgath]

Hiya

had another look - according to LR book (1st ed, Tom Sheppard, 1993) so 2nd ed may have corrections

V8 90's had 1.222 (this is 5speed)
Tdi/4cyl 90s 1.41
110 V8/tdi 1.41
110 4cyl 1.667

Ascroft has a page http://www.ashcroft-transmissions.co.uk/part_8.html#pa1 where details of LT230 are posted.  I guess jeep94 spoke to him about his LT230 and was told to get 1.41s

hope this clears up what I wrote earlier (got the it wrong for 4cyl 110 in previous post I meant 90s)

[BigSi]

1.4 is a standard ratio for 99% of defenders - are you sure this was the advice from Dave?

Yep, he wrote;

 "I think you have it geared too high if it doesn't pull 5th gear at all, if this is the case you need to drop the ratio to the defender 1.410 ratio,"

[smo]

So why were you originally asking about 1.192:1 ratio t-box's???

[BigSi]

That's what it has now.  :)

[smo]

That's what it has now.  :)

LOL - right, gotcha, now i understand - well if you decide to sell it....