As terran pointed out, you would need at least 10 years of working in the US to be eligible to US-based benefits.
This is not correct as a general proposition (as your own secondary source also notes). There are a great many exceptions to the above rule. I don't propose to summarise them in this post, but some of them may be relevant to the OP.
My 3 years of USA SS payments translate ... into 3 years of credit towards the Canadian CPP earned credits. I don't get any $ from usa in retirement, ... but the cdn benefit is increased a bit by it.
Unfortunately, this isn't true. I remember reading a secondary source that also made this claim, but the claim has no basis in law.
To analyse the quoted claim, we start from the proposition that, in Canada, treaties and other international agreements do not have the force of law.
Baker v. Canada (Minister of Citizenship and Immigration), [1999] 2 SCR 817, 1999 CanLII 699, at ¶ 69. This means that we do not need to read the international agreement to analyse your claim. Instead, we can look at only Canadian domestic law.
The statutory basis for the Canada Pension Plan is a statute called the Canada Pension Plan, RSC 1985, c C-8 ("CPP Stat"). The formula for the "retirement pension" is set out in CPP Stat §§ 46
et seq. I won't get into the details of the formula, but it suffices to say that the only earnings that are taken into account are the beneficiary's "total pensionable earnings". Through a series of statutory cross-references, we eventually find that if an employee did not actually contribute to the Canada Pension Plan in a given year, the amount of pensionable earnings taken into account for that year "shall be deemed to be zero". CPP Stat § 52(2).
In other words, unless contributions to the Canada Pension Plan were withheld from your paychecks in the United States or you otherwise paid the CPP premiums through your Canadian tax returns those year, your work in the USA did not count toward the Canada Pension Plan and will have no effect on your Canada Pension Plan benefit whatsoever. Harsh, but true.