Diff ratios

Hi Guys

I'm re-building my s3. I've acquired a V8 and a Salisbury rear axle.

I've been told that there's a difference between the front and rear ratios. What effect will this have and how can I overcome it ?

Any help would be greatly appreciated.

Cheers

If the diffs have 2 different ratios you will destroy your gearbox when you select 4wd (high/low) because the front wheels will turn faster than the rear does.
.... Use the same ratios !!!!

Yes, you'll have to have diffs the same ratio or it'll be undriveable and break something pretty immediately if you try and use 4wd.

I think Salisbury diffs are very hard to change the ratio on, needing special tools to disassemble and very rare parts. It will be easier to match the front to the rear, you'll have to do some turn counting to work out what the ratios you've got are.

Keep one wheel or hub fixed and turn the input flange, count what turns you need to make the free wheel/hub turn once, then divide by 2 to get the diff ratio. Don't do it without keeping one wheel still or some differential action will happen and you'll get a wonky result.

Standard Series are 4.7:1, the common replacement is 3.54:1 from range rover or disco. Stage 1 Series Land Rovers had a Salisbury axle and 3.54 diff, maybe you have one of these? In that case you need a Range Rover Classic or early Disco diff to fit into your front axle to make them match, that's easy enough.

Let us know the results.

i'm going to assume that the salisbury came out of a standard 109 not a stage 1

if from a standard 109 it'll be a 4.7:1 ratio

from a stage 1 it'll be 3.54:1 (i think, not sure now, bugger)

if it is a stagey axle the problem is real easy to sort by putting a 3.54 diff in the front axle



4 axle stands (2 to support landy, 2 to support hubs), 1 diff gasket (and diff) a tube of silicone to seal the swivels to axle tube, job jobbed in a couple of hours (don't forget the EP90)

its not too difficult changing ratio on a salisbury axle but does require resetting diff onlt special tool needed is one to hold drive flange while adjusting nut to squash collapsible spacer to set pinion preload

Thanks guys.

Looks like I have some work ahead of me. The axle was sold as being a Salisbury axle from an 88 rather than the usual 109.

timmy's tonka said:

Thanks guys.

Looks like I have some work ahead of me. The axle was sold as being a Salisbury axle from an 88 rather than the usual 109.

Click to expand...

it'll still be a 109 axle but it'll have had the spring perches moved to suit the 88" chassis/suspension

and be 4.7 ratio so should be ok to fit