You need ¼ drive & are 8mm tube socket with a 2" extension (4" extension for the rear passenger left glow plug), replaced mine 2 days ago.
I used
http://www.ebay.com.au/itm/6x-Diesel...item1e7f15ddfe
10mm are the wrong size.
compatible part numbers:
GX2148, GLP197, GLP202, 05175756AA, DP51, Y-8002AS, DG-194, 0001595001, 0011597101, CE-013, ZPN-03877
Don't forget to use anti seize.
Need to remove the turbo intake hose, the rear brackets that hold the engine cover on & the small wiring guide two 8mm bolts for the front drivers side (right) glow plug.
Once you crack the glow plug they should undo by hand, if they don't they may be carbon build up stopping them. I have one with this problem & will need to source a puller to get it out, may try decarbonizer over a couple of tanks & see how I go.