138k Boxer engine ok?

[Pablo Uno]

Hi, recently acquired Boxer 2.2 smokes a bit for first hundred metres from lukewarm. Also clunking between 3rd&4th gear. Do people change either lump or box at this mileage? 2013 plate.
Would like to keep van for 10 years.

 

[Clivefog]

Just run in at 138K.
What colour smoke white or black?
Change gear box oil as a first step.