Had an 01 3500 RAM 5 speed pre DEF pre Exhaust brake. Had a pacbrake installed. Loved it.
Upgraded to 2014 5500 RAM automatic (have to special order stick shift). was skeptical about exhaust brake although it comes already installed. Automatic's with exhaust brake are not as good as with stick shift... however... I had the tow / haul package installed and TOGETHER tow / haul ON and exhaust brake it works wonderful on new automatic transmission truck. Happy with automatic transmission so far and pulled 5th wheel trailer in colorado mountains and have to use manual brake very little :)