Thread: Diff ratio recommendations

Originally Posted by isuzurover

Only in HIGH range - so won't help offroad. And I would be surprised if it was lower than the defender 1.4:1.

The 2.5 NA 90/110s had 1.6:1.

A few searches and a bit of reading would have avoided all these questions...

I HAVE searched for more info on the 2lt..to no avail.....It must be tough knowing everything
Jus kiddn man. Thanks for your help

Originally Posted by moorey

I HAVE searched for more info on the 2lt..to no avail.....It must be tough knowing everything
Jus kiddn man. Thanks for your help

That's not what I meant - I meant that a few seconds with google would tell you that all LT230s have the same, low range, and that you can buy any gearset you want (no need to import a whole t-case) from Ashcroft or others (who make the diff gears you want to buy )

A minute or so googling and I found:

List of Serial numbers and corresponding Ratios

All stock LT 230"s have a low ratio of 3.321, the following list refers to the high range ratio.

12D = 1.667 LT 230R

13D = 1.410 LT 230R

14D = 1.003 LT 230R

15D = 1.192 LT 230R

20D = 1.667 (2.5 N/A 110),

22D = 1.410 (all 4Cyl 90/110 bar above),

25D = 1.410 (V8 110 LT 85),

26D = 1.003 (RR Classic 3 speed auto),

27D = 1.192 (early RR Classic),

28D = 1.222 (RR and Disco I),

29D = 1.192 (V8 90 LT 85),

32D = 1.222

34D = 1.410 (2.0 Disco I),

36D = 1.211

38D = 1.211

40D = 1.211 (NAS/Japan 90&Disco),

41D = 1.211 (Disco II, diff lock stud),

42D = 1.211 (Disco II, diff lock stud),

43D = 1.410 (90/110 TD5),

57D = 1.410 (90/110 TD5),

61D = 1.211,

62D = 1.211,

68D = 1.211,

69D = 1.211,

70D = 1.211 (Disco II, no diff lock),

LT 230 Transfer case comparisons

1.003 > 1.222 = 17.92% Drop
1.003 > 1.410 = 28.86% Drop
1.003 > 1.667 = 39.83% Drop

1.222 > 1.003 = 21.80% Raise
1.222 > 1.410 = 13.33% Drop
1.222 > 1.667 = 26.70% Drop

1.410 > 1.003 = 40.57% Raise
1.410 > 1.222 = 15.38% Raise
1.410 > 1.667 = 15.41% Drop

1.667 > 1.003 = 66.20% Raise
1.667 > 1.222 = 36.41% Raise
1.667 > 1.410 = 18.22% Raise

For those considering a ratio change the following may prove useful.

MPH per 1000 rpm = 2.976D/ MTR

D Tyre diameter in inches (more accurate to use 2 x rolling radius)

M Typical 5 speed manual box, select a ratio 1st 3.60 These ratios will vary a little between box types 2nd 2.11 3rd 1.40 4th 1.00 5th 0.77 Rev 3.43

T Transfer ratio select a ratio

High 1.003 1.222 1.410 1.667 Low 3.321

R Differential select a ratio 4.70 S 4.11 L 3.54 S L Special
S stock

So against a defender you drop 15% on diffs but lift 10% on tyres. Given that it will be a fairly light vehicle I would go with the Disco Box and those 4.1 diffs.

I think the above data is originally from the Ashcroft site.

So - the 2.0Mpi disco has the same transfer case as an AU defender, so you would be wasting your money importing one.