Mobil SHC 634 gear oil is or was manufactured by Mobil Oil Corporation.

In this cross reference tool, PSC offers this Mobil SHC 634 and/or equivalent products of the similar quality and performance. 

See below for the equivalent products and select the 'View Manufacturer Info & Data Sheets' tab for the safety data sheet, as well as product data sheets to compare specifications, approvals, properties, and performance characteristics.