"The transmission can be from a 53 or a 55" ??
If the truck has a closed driveline (torque tube) it would have the 53 transmission configuration.
All 55 3 speed transmissions are only used with open driveline applications including the 55 first series. Someone may have replaced the torque tube rear end at some point and installed the later transmission. This information is something a rebuilder would need to know as they are vastly different. As Jerry states, it could be something besides transmission noise.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine