"The bond market is listening. The influence of the Fed has greatly increased and the market, it is getting kind of old school where the market listens to what the Fed says," Gundlach said on CNBC's "Halftime Report."
The Federal Open Market Committee is scheduled to release its meeting statement at 2 p.m., ET. Fed Chair Janet Yellen is scheduled to hold a news conference at 2:30 p.m. Traders widely expect the central bank to raise interest rates.
"What's really important isn't the interest rate increase that we all know is going to happen," he said. "It is what happens with the Fed's rhetoric."
Last week, Gundlach said he expects the Fed to begin a campaign this month of "old-school" sequential interest rate hikes until "something breaks," such as a U.S. recession.
The DoubleLine chief said Wednesday that so far since the U.S. presidential election he has seen no indication of a recession. He said leading indicators appear strong and he expects a short-term rally in Treasurys.
"Don't see a recession coming at all. Back last summer, there was some dicey-looking stuff," he said. "All that changed with the election."
Gundlach, who oversees more than $101 billion at Los Angeles-based DoubleLine, said U.S. economic data support a rate increase, and further rises this year, after a series of false starts in 2015 and 2016.
"Confidence in the Fed has really changed a lot," Gundlach said on an investor webcast last week.
On Wednesday, he said one thing investors have to look out for is "risk is starting to get risky."
"The stock market is going sideways these days instead of up," Gundlach said. "And the junk bond market ... that's starting to go down a little bit."
— Reuters contributed to this report.