Identifying Diff

[xain]

Hi all,

I was looking at the diff on my 500 the other day out of curiousity, and it doesn't look like either the BTR or GKN diffs in the bible. It was a round back-plate without heat-sinks, rather like a truck one.

Could this be a Hydratrak?

[joospeed]

that will be BTR then .. the GKN has fins and the rear casing is about one third of the diff unit and alloy, on the BTR only the very back casing is separate and alloy.