When crawling along in D2 in heavy slow moving traffic, the car revs and tries to go into D3, very briefly accelerating then stutters.. only happens in very slow moving traffic- stop start scenario. 

i have auto, manual and sport mode gearbox.

any ides?

A good start would be to get the car scanned for error codes, because of the complex electronics controlling every aspect of the engine and transmission.

Thank you - i have had a diagnostic check done and nothing came up..

 

Well what about gearbox oil levels? Or is that something else you have already done?

Hi there,  both oils have been changed on the gearbox .. I thought it could be that so had them changed, but to no avail..

 

I will keep Investigating.

thanks for the posts.