When we sell an exhaust brake to customers who own trucks earlier than 06 models we also sell them a kit to lock the torque converted when they slow down... .
Under the current programing, the TC will almost free wheel when you let your foot off the throttle when you slow down... this is like putting your foot on the clutch pedal...
With an exhaust brake you need the TC locked, just like you need the clutch engaged when the truck starts to slow down... . this allows the power from the rear wheels to pass through the transmission to the engine for the exhaust brake to work... .
On truck 06 and up..... the factory has finally seen fit to put the correct software in the transmission to allow this lock up... about the same way some of the bigger transmissions used on mid range trucks...
Hope this helps. .