The difference is the TR4 and the TR4A rack & pinion assembly is their overall length. (TR4 1023mm, TR4A 1003mm). The change in overall length is achieved by the length of the inner ball joint assemblies.
Fits LHD TR4A.
These assemblies are factory lubricated with lithium grease (not oil as per the originals). They are sealed, and are not meant to be re-lubricated.