Is "try to" redundant? In other words, is it implicit in "to undertake"?
"If a dispute arises under the contract, the Parties will undertake to try to reach an amicable settlement before taking legal action."
Not at all. It's instrinsic to the meaning of the sentence. If the Parties undertook to reach an amicable agreement, they'd never have to take legal action. They are only constrained to try.
So, "try to" is not implicit in "undertake" in this case.