What is the difference between ( Transmittal & Submittal ?

Transmittal is a cover sheet of deliverables which tells to reader that documents are being issued for information, approval, construction or as-buit etc. Submittal can be drawings, letter, invoice etc.

Submittal is a kind of document pertaining to material samples, shop drawings and product specifications for approval prior to installation and construction.

Transmittal in general, a cover letter or reference to submit a document, materials or drawings.

transmittal is details of ,what ever documents want to send other party , Submittal is Details of whatever documents is submitting for approval 

If Transmittal is vehicle Submittal is passenger!  

Transmittal is a cover letter and indicates purpose of attached submittal.

Transmittal is the cover for the attached and submittal are deliverables

Transmittal is exactly an envelop telling what and where to deliver. Submittal is what inside the envelop, the actual deliverable(s).

For most purposes, Submittals and Transmittals are documents exchanged during a building project, typically amongst Architects, Engineers and Construction (AEC) professionals. Most industries consider Submittals to be more of a preliminary step in the building process, sent with the expectation of forthcoming revisions or a request to be answered therein. Transmittals are typically sent as records, documentation or required materials (such as CAD drawing files) for the project. While Transmittals are still open to revision and collaboration, the sender is usually not seeking such changes or requesting the type of feedback as though it were a Submittal.(other than receipt confirmation of the Transmittal)