To load a CLOB in to Teradata you need to use TPT. TPT will also allow you to extract that data from SQL server, so I think you need a single TPT script:
- use the ODBC operator to login to SQL server and run a SELECT statement that extracts the data
- the output from the ODBC operator is passed into a TPT Inserter/Stream operator (as appropriate) to load into the Teradata system
If you're not familiar with TPT try the following manuals:
"Teradata Parallel Transporter Reference" gives the syntax for the operators named above
"Teradata Parallel Transporter User Guide" talks through this type of processing (Chapter 5) including an example of moving CLOB data into Teradata ("Job Example 3: Loading BLOB, CLOB, and JSON Data" - page 106 in the TTU 15.10 manual).