Form 3520 would not be filed for a pension. It is only used if you receive a gift or inheritance from a foreign individual or estate as detailed in this blog.
Form 8938 would be required when the value of the asset in the account exceeds a certain amount at the end of the year or during the year but is dependent upon your filing status as well and whether you reside within the United States. For example, someone who is single would meet the filing threshold if the foreign asset has a value of $50,000 on the last day of the year or $75,000 at any time during the year. Please see the section titled "Types of Reporting Thresholds" on this link for more details as it applies to your specific situation.