I have a Vauxhall Vivaro and have had no end of problems with the gearbox/electrics. Is this common?

I bought my van2 years old and 14000 miles. I am on my second gearbox ( I have been told it Has a renault Laguna gearbox which cant cope with the load) and constant engine managment problems. I have also had worn CV joint and wheel bearings going. It's only don 40000 miles. The garage i take it to to be serviced tells me they are all the same and renault make crap vans. Has anyone else had the same joys that i have had?