Yes, you may use +4 in your Ram. From
TSB 21-006-01:
A new transmission fluid (ATF+4® - Type 9602) has been developed and is being used as factory fill for all vehicles with Chrysler automatic transmissions. Until now, vehicles originally filled with ATF+2 or ATF+3 were to be serviced with ATF+3. Effective immediately, it is recommended that all vehicles with Chrysler automatic transmissions except for 1999 and earlier minivans be serviced with ATF+4. For all other applications the ATF+4® fluid offers significant benefits as outlined below.
BENEFITS
+ Better anti-wear properties
+ Improved rust/corrosion prevention
+ Controls oxidation -Eliminates deposits
+ Controls friction
+ Retains anti-foaming properties
+ Superior properties for low temperature operation
FLUID COLOR
Mopar ATF+4® is a World Class Fluid having exceptional durability. However, the red dye used in ATF+4® is not permanent; as the fluid ages it may become darker or appear brown in color. ATF+4® also has a unique odor that may change with age. With ATF+4® fluid, color and odor are no longer indicators of fluid condition and do not support a fluid change.
Part No. 05013457AA Fluid, Transmission, ATF+4® (Type 9602), Quart
Dave