The 48RE is the newer, stronger version. In the early part of the 03 model year (when I ordered mine) the 47RE was in production and could only be had with the Standard Output motor. If you got the HO it had to be the stick shift (NV5600).

Then the 48RE came out, and could be had with the HO. In 06 I believe, there was an update that allowed the 48RE to be used with the Jacob exhaust brake w/o warranty voiding or the need for an aftermarket box, and it also got tow/haul mode and OD lockout.

 

early 03 47re auto, 95,857 miles 3 recalls to fix minor problems and 1 lift pump @ about 70,000 miles. i love this truck.