The 'E' Type Forum

Does anyone know if it would be possible to fit the differential (2.88) (Not the entire IRS!!) from an XJS / DD6 / XJ12 into the series 3 IRS?

The reason I'm asking is that this might be the best method for me to solve the speedo discrepancy I have. Speedo displays 135km/h when I do 120km/h GPS. Doing this conversion, would have the added benefit of dropping cruising engine RPMs by 400 from 3300 to 2900.

Hi jagwit,

I can confirm yes, it is absolutely possible as this is what I personally fitted to my S3 & it worked very well as a very simple & relatively cheap (£250) upgrade.

The above said for 2017 I am about to remove it & replace it with the original 3.07 (Auto Diff) as I find 3100 rpm @ 100mph with the Jaguar O/D gearbox a little high geared.

Depending on equipment & skill set it is a very easy fit that shouldn't take longer than a weekend as all the original S3 brake discs / brake callipers & drive shafts fit with ease.

All you need is the actual diff (I used one from an XJS 5.3HE) & then drop the rear IRS cradle (complete) & then swap everything over & reassemble.

If you need any further details just let me know, I be happy to help.

XJS 5.3 HE on Left; XKE 3.07 (Auto) on the RIght:-
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XJS 5.3 HE Fitted ready for refitment:-
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I confirmed too. I ve done the same swapp.
Michel