Ok guys update for this thread thanks for your advice.

Well worth doing this job. It's actually very easy if you take your time.

I didn't break the infamous nipple either.


Vandalised/massacred vaccum-to-fuel regulator elbow - replaced - thrupence (or cheap)
Toasted spark plugs replaced - £30
Yellow O-Rings replaced - thrupence
Warped lower-elbow replaced - thrupence
Warped upper elbow replaced - thrupence
Cleaned throttleBody
Gaskets - £20



Engine now runs and sounds superb however,

Juddering and gearslip remain and has thus been exacerbated, this we think because engine now develops slightly more power?

So i'm now convinced we do have internal gearbox failure.

I conducted the proper temp level-check today - unit has leaked about 1ltr of ATF in less than 100 miles - sides of sump pan dry - rear cross-member evidence of leak - internal gaskets surely, somewhere.

I will be looking to remove our 5R55N unit and replace myself - will some programming be required by Jaguar?

Thanks again,