I had an 09, then a 13 plate old shape Vivaro 2.0CDTi. Good vans, both started getting unreliable with age and had to go. I paid more for a year old 204 LWB DSG PV than a new Vivaro BiTDi 140 would have been. Mine is a van, not a camper, but it drives like a car, and so much better than the equivalent Vivaro.
I use a father and son subby, who both bought new Vivaros. The son rags his around, the dad drives his a lot more considerately. The Son's has never had a fault in 2.5 years, the dad's has had fuel system issues, gearbox, master cylinder (wtf?), and all the associated time off the road. I just don't think they have the quality right. What's with a master cylinder failing on a new modern vehicle!
The engine and box in the Vivaros are the same 1.6D as a Renault Clio, but obvs with different ancillaries/ECU etc. No wonder they have so many gearbox issues with a torquey motor pulling round 2 tonnes plus...
My 09 Vivaro 6 speed gearbox died as it became noisy due to bearing failure. The bearings overheat and fail. The bearings have a woven copper strap attached to act as a heat sink to a part of the casing. The strap fatigues, falls off and the bearing overheats. One of the very common failure mechanisms. Small bearing due to compact size of the box it appears, but clearly not really suitable for longevity.