The bond market may be in big trouble, but we won't know for sure until we see how it reacts to a pullback by the Federal Reserve from its plans to taper quantitative easing (QE), says Bill Fleckenstein, president of Fleckenstein Capital.

"The Fed has lost control of the bond market," as interest rates have jumped since Fed officials began talking about curbing QE, he tells CNBC and Yahoo's Talking Numbers.

"But we won't know that for certain until the Fed is unable to taper or tapers a little and then has to untaper and then the bond market doesn't rally to a new high."

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The 10-year Treasury yield has soared to 2.89 percent from 1.66 percent May 2.

Fleckenstein expects the Fed to ultimately back off its tapering, because the economy isn't strong enough to withstand it. "The thought that the economy is strong enough demand this [tapering] is ridiculous," he proclaims.

If the bond market doesn't rally substantially after a tapering pullback, "then you'd know the bond bull market ended a year ago or something and that we're in bond bear market," he explains.

Fleckenstein says a bear market would likely stick around for a while. "These things tend to last a couple decades."

And it could get ugly. "We can have a bond market train wreck," Fleckenstein adds.

Shortly after the Fed began its QE four years ago there was talk about an exit strategy.

"Well, we didn't get an exit strategy. We got QE2. Then they talked about exit strategy after that. Then we got QE3 and QE4. Now they're not even talking about exit strategies. They're just talking about $75 billion or $65 billion instead of $85 billion," he notes.

Meanwhile, minutes of the Fed's July policy meeting, showed that central bank policymakers were "broadly comfortable" with the plan to begin trimming bond purchases soon.

"They'll probably start to taper in September," Josh Feinman, New York-based chief economist for Deutsche Asset & Wealth Management, tells Bloomberg. "They know that that's widely anticipated, and they haven't done anything to deflect those expectations."

Editor’s Note: Obama Blunder Spawns Massive Profit Opportunity