I have two worksheets, one has a large amount of data with maintenance tasks on it that reads like the following.

Col A Col B Col C Col D

001 Chassis Inspect Annually
002 Engine Inspect Annually
003 Glass Ensure Clean Every month
003 Glass Check for Cracking Every six months
004 Gearbox Inspect Every month
004 Gearbox Lubricate Annually
005 Lights Operate Weekly

This spreadsheet has over 2000 lines long and needs updating from another spreadsheet.

The other spreadsheet has the same information layout but only has about 700 with the only difference being Column D which is the task frequency.

I've tried using IF functions and AND functions to match the value in colums A,B and C on both spreadsheets but to no avail. The match function gets stuck with identical values in a column as it will only display the first value when it matches up.

Any help appreciated.
Any help would be useful.