Vehicle & Technical > Defender
Transfer Box Ratio
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:
--- Quote from: "jeep94" ---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
--- End quote ---
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:
--- Quote from: "smo" ---1.4 is a standard ratio for 99% of defenders - are you sure this was the advice from Dave?
--- End quote ---
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,"
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