Google's Gary Illyes said on Twitter yesterday that any type of 3xx redirect, a 301, 302, or any type, of 3xx redirect, does not lose any PageRank value along the chain. So if you redirect domainA.com to domainB.com or domain.com/pageA.html to domain.com/pageB.html using a 301 or 302 or any flavor, it loses absolutely zero PageRank.
Here is his tweet:
30x redirects don't lose PageRank anymore.— Gary Illyes (@methode) July 26, 2016
Now, this is not new. I asked John Mueller about this during the video hangout yesterday. I said, didn't you say this not just once but twice earlier this year, and he said yes - this is not something that is new. Although, back in 2010, 3xx redirects did lose value.
At the 17:22 mark into the Google Hangout on Google+ I asked John Mueller about Gary's tweet and he said at the 19:30 mark, "that's been a while" when I said if this is new. Meaning, 30x redirects have not lose value in a while, which is what he said earlier this year.
Just to be clear, in 2013, Google said that 301 redirect does not dilute. Here is the video from Matt Cutts on this:
Forum discussion at Twitter.