can anybody tell me if I can fit a 2010 on. 3.0 6 speed gearbox to a 2005 2.7 will it work or do I need lots of mods .
any help welcome.

CANBUS speeds are different between 05-09 and 2010 onwards, and so will not work

You need a box from an 05-09MY. Same gearbox as a D3 though, if that opens up your search window

Is it not the case that the box would work if the mechatronic unit is swapped over though (subject to it not having faults, of course)? Visiting from DISCO3.CO.UK
2006 Discovery 3 TDV6 Auto HSE Zambezi Silver

hi I take it that the mechatronic is interchangeable as a complete unit , my gear changes are fine and no fault codes , just seems to be the torque converter that's the prob. but car has 106k and seems wise to change both .

If it's just the TC, just change that (but ASAP, before it's too late). Mine's recently been done, and now it's all smoooooth again.  Visiting from DISCO3.CO.UK
2006 Discovery 3 TDV6 Auto HSE Zambezi Silver