years after a divorce can you go back and contest the settlement

No.

No.

In general, after so much time has passed, it would be extremely difficult to get the court to revisit the property division.

However, in some circumstances, there may be valid reasons to ask the court to review. For example, if the other spouse purposeful hid information and misled the court and the spouse as to the nature of the property in question, and the misled spouse just now finds out the true information, there may a good reason for the court to review.

In some settlement agreements, there are clauses that specify that, if one spouse hides assets and is later discovered by the other spouse, most or all of the hidden (and now discovered) assets would be awarded to the other spouse. The agreements may provide another basis to ask the court for review.

You should review your specific facts with your attorney to see what legal options may be available to you. Keep in mind that you may have an uphill battle.