Reply from another post:
It's not the engine that's the weak link. Toyota does not build strong transmissions. They never have. Stout engines, weak transmissions. Been that way for years.
You don't hear about broken gearboxes until they start shifting badly. Someone pulls one apart and all the bearings are shot. Just like clutches, gearboxes are rated by torque. NOT horsepower. All the turbo kits dramatically increase torque from the engine. The supercharger does not increase peak torque much at all. I'm dead certain there is a reason for this, and I'll bet the E350 starts burning up bearings in relatively short order.
Keep in mind, a gearbox is typically designed for a 250k mile (minimum) service life. If it dies in less time, it is being stressed beyond the design tolerance. And gearboxes fail because their bearings fail. Not because the gears have problems, but because the bearings won't live to full service life. As soon as the bearings start to go, the gears chew themselves up in short order. It's all about bearing life...
It's not the engine that's the weak link. Toyota does not build strong transmissions. They never have. Stout engines, weak transmissions. Been that way for years.
You don't hear about broken gearboxes until they start shifting badly. Someone pulls one apart and all the bearings are shot. Just like clutches, gearboxes are rated by torque. NOT horsepower. All the turbo kits dramatically increase torque from the engine. The supercharger does not increase peak torque much at all. I'm dead certain there is a reason for this, and I'll bet the E350 starts burning up bearings in relatively short order.
Keep in mind, a gearbox is typically designed for a 250k mile (minimum) service life. If it dies in less time, it is being stressed beyond the design tolerance. And gearboxes fail because their bearings fail. Not because the gears have problems, but because the bearings won't live to full service life. As soon as the bearings start to go, the gears chew themselves up in short order. It's all about bearing life...