Current part number is a 6H3364 Group number. The group consists of a 9F4113 capsule and a couple of o-ring seals.
Here is an example of after market....
http://www.ebay.com/itm/6H3364-for-Caterpillar-CAT-/291575591852?hash=item43e34273ac:g:gdMAAOSw4HVWCJjU&vxp=mtr