Meh, this ain't the 1960's and 1970's anymore... Crap just last longer now. Just like regular cars. Where are the majority of the warranties now are over a hundred thousand miles for 4 wheelers .... The only thing that breaks with big trucks now. For the "most part"( <----two key words) it's electrical crap sensors and whatnot.. and the dam DPF system. ... If you're changing your oil every 10000miles for a B service either you have a really bad engine or just throwing way good oil..... There's a reason why you don't see car repair shops in every gas station anymore... and the same for big trucks too....
That is part of it, yes. We have lost a lot of techs via layoffs and attrition. But there is more to the story. Earlier this year, the shop training staff completely re-vamped the PM process. It is much more inclusive and therefore takes longer to complete. The goal is to keep the equipment out of the shop between PM services. Which is certainly a good thing for the drivers. The only drawback is that the PM does take longer to complete. We also are doing more repairs during a PM, as that is another standard that changed- if a wear item is OK now, but will likely fall below minimum DOT specs before the next PM, then we replace the wear item at the PM. So this could add more time to a service, but means the driver doesn't have to come back a month later.