The FKS and FKE models have been around since the 1960 and are in every industry in the UK. Companies like Jaguar have used them since the mid 90's successfully. The early Titan trucks had issues, the German made ZF drive axle had many issues, for that reason the axle was replaced with a Axle-Tech drive axle in 2001, so the parts problem and poor durablity must be related to a pre 2001 model. The General Motors engine might not be perfect its still the best choice for that size truck, Many manufactures are using that engine.