The G56 Ratios did change. The two transmisions are coded AD for the older version and AE for the newer Version.
The gear ratios and the angle of the shifter stub a changed with each version. The version change was in Dec '06.
AD Trans: verticle shifter stub
1st = 6. 29, 2nd = 3. 48, 3rd = 2. 10, 4th = 1. 38, 5th = 1. 0, 6th = 0. 79
AE Trans: angled shifter stub
1st = 5. 94, 2nd = 3. 28, 3rd = 1. 98, 4th = 1. 31, 5th = 1. 0, 6th = 0. 74
OD's from other trans:
G56: . 79 or . 74
NV5600: . 73
NV4500: . 75
AISIN 68RC: . 77 (5TH) AND . 63 (6TH)
68RFE: . 81 (5th) and . 62 (6th)
48RE: . 69
info is from the klenger gear chart
http://www.klenger.net/dodge/general-reference/gear-speed-calculator.pdf
Thanks
Deo