Classic/Antique Car Repair: 49 Cadillac Hydramatic gearbox, hydramatic, valve pressure

Question
Gearbox has a problem/1st to 2nd gear shift is fine' 3rd to 4th is also fine' the 2nd to 3rd gear change bangs into gear and is harsh.
The gearbox was Overhauled in 2006 and to my knowledge the seals, bands,ect were replaced.
could you please help with this problem
Many thanks

Answer
This transmission was never known for it's smoothness in fact when it first was let loose on the motoring public with the big V-8 it was known as "4 jerks and you are away". However at this point I would suggest a fluid change and a band and linkage adjustment. In the early transmissions shifts were synchronized by band adjustments. By the late 50's and early 60's the technology of the hydraulic controlled automatic transmission had progressed enough so that band adjustments were no longer needed. The linkage adjustment is to make sure that the transmission control valve pressure is matched to the throttle position. If this does not help then it is time for a pressure test on the transmission and internal repairs.
Good Luck. Brad