The H55/splitcase came from MAF with the mainshaft and different rear bearing retainer changed so that the parking brake from the one piece case could be used on it.
The guy that owns this truck does not intend to pound rocks with this vehicle. After the trans is installed, I will look at the skid plate and see what can be done, but as of right now, he does not see the need for a 40MPH rock rated skid plate.
There will be something under there protecting this though.