The installation of my Fr & Rr Harrop lockers has just been completed last week.
What mileage does your truck have at the moment.
Some issue related feedback.
At the time I told the installer to perform complete diff overhauls at the same time (mine has 287000km) comprising carrier bearings, pinion bearings and oil seal.
When resetting the crownwheel and pinion gear interface wear and backlash it is extremely important that they re-match to the existing wear marks on the crownwheel and pinion.
If not you will get diff whine (this was the case with mine)
Mine had to be removed and reset an additional 2 times to get this 97%
However if yours is a low mileage truck you probably wont have this issue.