DoubleLine CIO Jeff Gundlach was on CNBC after the Fed decision (which he called the right one) and touched on gold prices, which hit $3700 for the first time today.He noted that gold is up over 100% in the past two years and 45% year-to-date, a move he called 'ridiculous'."Now even the gold miners are getting involved, which suggests to me that retail investors are starting to join the momentum trade on the gold market," he said.Gundlach noted that he's been a gold bull and predicted $4000 earlier this year. He took it a step further today and touted another $340 gain, from current levels, or about 9.2%."I think almost certainly gold will close above $4,000 by the end of this year," he said.Gundlach also hinted at a big part of the reason that gold is up and the US dollar is down this year. The job interview at the Trump administration for Fed chair candidates is: "Will you do what I tell you to do?", he said. This article was written by Adam Button at investinglive.com.