Where can I get a top carrier roller or the right part number for a Caterpillar D3B, and is it normal to find oil in the starter from a wet flywheel?

[Mr. McTuggart]

Working on a Caterpillar D3B and need some quick advice.

Where can I find a top carrier roller or confirm the correct part number? Also, I noticed a bit of oil inside the starter (near the flywheel gear). Is that normal for these machines (wet flywheel?), or should I be checking seals or something else?

Appreciate any help.