Res Judicata question Forum

[newyorker69]

Ok I know the elements for res judicata:

1. same claim
2. same party or privies
3. after a final judgment
4. "on the merits"

we read a case, Martino v. McDonald's System, Inc. where in the original case, the parties settled their case and put the settlement in a consent judgment. so the guy who basically "loses" in the settlement case (he was the D) tries suing himself later on a different theory. the court held there was no R13(a) preclusion because that pertains only to res judicata based on pleadings and he never filed an answer with the court in the first case before he settled. however, the court held there was preclusion based on a "common law compulsory counterclaim."

i understand how this new suit directly attacks the first consent judgment and how for policy/efficiency reasons he shouldnt be able to file suit again. however, what happens if the two parties settled and never solidified it into a consent judgment. can you sue a few years later on the same claim? i guess im asking if a contractual settlement agreement that is not solidified in a consent decree/judgment is considered "after a final judgment" and "on the merits" as far as res judicata is concerned.