Is it normal for a 966C to leak from the bell housing area?

[Gryks Machines]

I've got a Caterpillar 966C wheel loader and recently noticed a leak coming from the bell housing area. It's not engine oil-it looks different (maybe transmission or hydraulic fluid), and it's seeping right between the housing.

Just trying to figure out whether this is common on these older loaders or a sign of a bigger issue.