Maxi drive reduction gears

Can any one tel me the final drive of a lt 230 with 4.12 difs and 49% maxi reductions

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Originally Posted by isuzurover

My gears (in fact whole T-case) just arrived today - Thanks MR/Warren and Jamie!!!

To answer the tooth count issue, they are as follows:
26/41/23/72
Input/Intermediate/Low-Int/Low

Which by my calculation gives 4.94:1 low - exactly 49% lower than 3.32:1

The 30% gears are apparently
26/41/20/55

The low gear for the 49% set is only 3mm larger in overall diameter than the 30% set. 184 mm as opposed to 181 mm.

The 49% instructions are added at the back as an addendum to the 30% instructions. A fair bit more case grinding is needed compared to the 30% set. If you look at the RHS of the case from the outside, there is a small indent about halfway up. The thickness of that section is reduced to ~3 mm.

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Quote:

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Originally Posted by disco_thrasher

Can any one tel me the final drive of a lt 230 with 4.12 difs and 49% maxi reductions

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Which gearbox and what variant (V8 or Tdi)?

49% MD reduction is 4.95:1

So 4.12 x 4.95 x 1st gear ratio

e.g. 3.6:1 first will give you 73:1

Sorry R380

Quote:

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Originally Posted by isuzurover

Which gearbox and what variant (V8 or Tdi)?

49% MD reduction is 4.95:1

So 4.12 x 4.95 x 1st gear ratio

e.g. 3.6:1 first will give you 73:1

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First varies from 3.321 to 3.692 in the r380 depending on what it was fitted to.

3.692 is more common (most defenders, tdi discos etc)

3.321 was in manual v8 Disco 1's and 2's

so you will be somewhere between 67.7:1 and 75.2:1

(calcuated from )

3.32 (tc ratio) x 1.49 (reduction) x 4.12 (diffs) x (3.321 or 3.692)

Thanks Pete and isuzurover

I get some noise in high range with the 30% gears in my Defender.
Some one said that this is a characteristic of the low range straight cut gears when they are free spinning.
The noise is especially noticeable on over-run.

Should I be concerned or is this considered normal?

James

Quote:

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Originally Posted by James

I get some noise in high range with the 30% gears in my Defender.
Some one said that this is a characteristic of the low range straight cut gears when they are free spinning.
The noise is especially noticeable on over-run.

Should I be concerned or is this considered normal?

James

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Normal.

My white rangie 30% gears
[ame="http://www.youtube.com/watch?v=Nz1ZSkWMh38"]Ellis Track August 2009 Part 2 - YouTube[/ame]

Quote:

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Originally Posted by isuzurover

I asked for 49% - we will see what turns up. I have to grind part of the case down to only 3mm thick to fit the 49% gears!!!

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Who are you ordering them from?
How much are they out of curiosity, as I want to do the same soon.

I've been told the 30% reduction gears are all you need for a deefer and they are stronger than the 50% gears.

How about the Ashcroft underdrive? How does it compare price-wise and use ??