I would strongly advise the use of grease and not oil to lubricate the trunnions.
There were some design changes made in attempts to cure the understeer that the Marinas suffered from.
Primarily this increased the thread engagement length between trunnion and swivel pin.
The fundamental reason for failure of the setup is lack of maintenance. If you do not strip clean and grease the trunnions on a regular basis, or as a minimum re-grease them, with an excess of grease, driving the old grease out then problems will occur, whether you use the standard or Walford Trunnions that are intended only to replace the worn or corroded thread on the swivel pin.
An interesting document describing the changes to both the trunnion and swivel pin can be found here or there
