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Tell me I can't do this

I've just had an idea - it's so obvious it must be wrong!

I want to raise the gearing on the S2a to make it a bit easier on the road. Overdrives and high-ratio t-boxes are expensive and I've just spent all my pocket money on a new head and carb.

I also have a trialler (V8 auto with 90 axles) which may well be a better trials vehicle with lower gearing - better control down hills etc .

Someone told me that the 4.7 diffs in the Series are a straight swap for the

3.54 diffs in the 90 axles. This would result in a 32% increase in gearing for the S2a and a decrease of the same for Tiggrr.

Is it a straight swap, and would I need anything other than new gaskets?

I'm sure I must have missed something. Fingers crossed...

Reply to
Richard Brookman
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3.54 ratio Range Rover Classic diff heads are a straight swap - they've got 10 spline axles (as you IIa should have if nothing's been changed). And aside from new gaskets they are indeed all you will need. The only downside is that they raise the drive ratio across the board - so low range is not as low as it previously was. A happier medium is to use Rover 90 diff heads (also a bolt in fit) that are 4.1 ratio. I've run with both in my IIa and I feel that the 4.1s give a more usable package overall (so they are what's in there at the moment).
Reply to
EMB

If your 90 axles are late ones make sure at least one of the cast diff housings has an oil filler/level plug hole on the side and put that one in the rear axle or you may have trouble getting oil in it after fitting. It's easier to weld a fitting in the rear diff pan whilst there is no diff fitted for obvious reasons. Range Rover Classics are fine spline diffs with no side oil fillers but early (two door types) usually have them and are 10 spline.

It doesn't seem like you are going to spend money playing with different ratios but if you * do * then the older Rover cars were, I think, 4.3 :1 and

3.9 :1, but not 4.1 as ISTR. I don't think you would find a pair of these anyway today.

HTH Martin

Reply to
Oily

Thanks EMB and Martin. As long as the 90 axles contain 10-spline diffs (easy to check) I can do the swap and see how it goes. In fact, all I have to do is swap the rears and remember to stay in 2WD. If the 90 diffs prove too much for 2.25 litres of naked power, I can always swap back and look for something in the middle.

Thanks for the help.

Reply to
Richard Brookman

On or around Mon, 8 Aug 2005 20:51:04 +0100, "Richard Brookman" enlightened us thusly:

the new old toy (now christened Edward II) doesn't feel as though he needs any higher ratios. Mind, the LWB is a lot heavier than an SWB - the SWB series II would pull to an indicated 77, and revved rather a lot in the process.

Reply to
Austin Shackles

so Austin Shackles was, like...

The S2a hasn't been above 65 in my ownership, and that was downhill with a following wind. 50-55 is a good cruise, and it feels as if it will pull a lot more, but the revs are high. I'm hoping higher gearing will let me drive at the same speeds with less need for ear defenders.

Reply to
Richard Brookman

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