Hi

Did you ever resolve this issue? I have a Volvo V70 D5 AWD -11 (built 2010) with the exact same symptoms. Runs and changes gears fine when cold but as soon as the gearbox fluid reaches 70⁰C (158⁰F) it starts to flare on every upshift. Not much but noticable. 50-200 rpms and then settles quiet ...