The transmission cover change is designed to give access to the transmission bellhousing bolts. The trans mount crossmembers are heavier and designed so that the center sections unbolt. The brake lines are re-routed to run behind the transmission tailhousing. It is designed so that the transmission can be removed from under the truck for service. There is actually a special tool that hooks between the frame rails and supports the rear of the engine as the transmission bellhousing is actually the rear engine supports. Bottom line is that due to the size and weight, provisions were made to aid serviceability.
