Gearbox change - engine flairing

[Bleah]

Hi peeps,

Nissan Stagea Autobox

The engine flairs inbetween some gear changes. Mainly with the overdrive off and also mainly under light to medium load.

If I boot it, it locks into gear pronto and does not slip at all.

I was wondering what your thoughts were on what is causing the issue.

My Main thought is oil pressure or a weak servo but I am not great with Auto Boxes - infact quite useless.

The Stagea Diagnostic comes back with 10 short blinks which means - no gearbox issues.

Is there anything else I should look for before I take it off?

[Bleah]

just to add:

it does this from stone cold, and is EXACTLY the same when warm.