My '04 WG have exactly the same diff as you Zappa916, part number is a perfect match and even looks the same.... the magnet test proves that mine is an aluminium centre housing (44A does represent aluminium).
The 44A is what we have in the 2.7 CRD, the 44HD is for the V8's.
My build sheet shows:
Build code DMD: Axle Ratio - 3.55;
Build code DRK: Axle - Rear, Dana 44/226MM;
Parts list for '02 & '04 WG has Dana 44M in the image, however axle housing P/N is listed as 05093060AA, not the 52104597AC stamped on our diff's.
The P/N 05093060AA appears to be the 3.73 for the VM 3.1, whereas our 3.55 P/N 52104597AC is spec'd for the MB 2.7
See
http://d44tech.com/Dana_44A.html for a comparison between 44 and 44A
From Drovers parts list:
"REAR AXLE BEARINGS:
Diff:..Dana 44A...........44/226mm...........Timken Set 31...plus Oil Seal Timken 2146........Aussie bearing shops may show nil listing so you want a Timken Bearing NP182140-904A1 with a lock ring K35961. Show them this pic to prove it. Numbers are confirmed as they are on mine, bought from Rockauto - AU$155.40 for 2 sets including freight. Genuine is AU$550 each side."
AU$129 via Amazon
I did my rear bearings with this exact Timken Set 31 about 5 years ago. No problem at all.