Don't do half the job! Whether you are trying to stop an oil leak or doing a transmission rebuild, the rubber seal in the driveshaft output flange is not the only thing that needs attention. If the bush that is pressed into the housing inside of the oil seal is worn, it can result in a number of problems and thus should always be inspected.
This bush has an OD of 1.4" , ID of 1.25.
See 22G421 (OD= 1.5" X ID= 1.375) for Hardy Spicer
Note: After the bush is installed it will probably needed to be reamed or honed to the correct size. This size will vary depending on the shaft OD. Resulting clearance should be around .0015.