Diff Ratio Change

[Staffie]

Have just finished installing V6 & Auto to SWB 97' need to look at changing the diff ratios or changing out the diff all together. Would appreciate any feed back or recommendations.

[karl]

use the search bar loads of threads about diff changes

[MinorMatt]

Mk4 and mk5 (which is what you have) 5 stud axles (which is what I am assuming you have) came with 5.14, 4.56 and 4.11 ratios. Which can be interchanged at will.

Earlier ones also came with 3.9 and 3.7 diff (which are very rare). These are not a direct fit, but all you need to do is change the differential center (the bit the halfshafts go in) to the later mk4/5 one.

The smaller the number on the differential, the more it will drop the revs for a given speed.

[Staffie]

Thx for the heads up. The information I have here in Aus is that my van is a 3rd Gen? It has six studs and depending on who you listen to the ratio is 4.63 / 5.13 The plan would be to get it down to 4.00 - 3.08 I think the only way I will be able to do that is fitting something like a 9" that have a wide variety of ratios available. I have been told by several differential businesses that there are 1 or 2 crown wheel and pinion sets available for the std housing.

[conrod]

I am guessing you have a Holden V6 and auto? The auto is overdrive, but even with the 4.63 diff ratio you will be short on gearing. What about fitting a falcon diff (Borg Warner) instead? Much cheaper than a 9", and you really don't need the strength (or weight) of a 9" diff for that engine. The 9" do suck a lot of power too, overkill unless you are running 400+ hp. I think you would probably pick up a Falcon diff for a few hundred bucks, lots of ratios, widths and LSD's available too. Just have to sort the wheel stud side of things out.