There was a thread asking about the function of the Tow/Haul switch on the 5.7 Hemi's and there was an excerpt from the manual within the thread:
On vehicles equipped with the 5.7L engine, use of ERS (or TOW/HAUL mode) also enables an additional underdrive gear which is not normally used during through gear accelerations. This additional gear improves vehicle performance and cooling capability when towing a trailer on certain grades. ERS 1, 2, and 3 are underdrive gears; ERS 4 is direct drive. ERS 5 (Overdrive) is the same as the normal 4th gear. When in the DRIVE position in first through fourth gear, the first tap to the left (-) will display the ERS designation for the current gear (the transmission will not downshift). For example, if you are in DRIVE and are in third (direct) gear, when you tap the shift lever one time to the left (-), the display will show 4 (ERS 4 is direct gear). Another tap to the left (-) will shift the transmission down to ERS 3 (the added underdrive gear). When in the DRIVE position in fifth gear, the first tap to the left (-) will downshift the transmission and display 5 (ERS 5 is the same as normal fourth gear). Another tip to the left (-) will shift the transmission down to ERS 4 (direct gear).
Do not downshift for additional engine braking on a slippery surface. The drive wheels could lose their grip and the vehicle could skid.
Screen Display 1 2 3 4 5* D
Actual Gear(s) Allowed 1 1-2 1-3 1-4 1-5 1-5
* Applies to vehicles equipped with 5.7L engines only.
NOTE: To select the proper gear position for maximum deceleration (engine braking), move the shift lever to the left “D(-)” and hold it there. The transmission will shift to the range from which the vehicle can best be slowed down.
Hopefully this helps....