Its very rare for a newer design Linde hydrostatic transmission to give any trouble, in the 5+ years I've been looking after a fleet of 392 & 394 Linde's we haven't had any issues with the hydrostatic transmission at all.

Only things that have actually failed so far on the fleet & caused a breakdown are:

Brake micro switch x 2
Coolant reservoirs x 3
Gas shut of valve x 1
Throttle pot x 3
Inner rear hub bearing x 1
Parking brake **** interlock spring x 2
Parking brake actuator lever x 1

Plus a loose starter motor cable connection.

The newer family of Linde IC counter balance's is the best you can get in Europe, there very well designed, there built to last & there easy to service / repair when needed.

It sounds like your local Linde dealer need's to invest in some training OR get someone else with experience to look at this truck.
If you don't know your way around Pathfinder you can really mess the truck settings up & causes all sorts of problems.