Recently we’ve seen a lot of Dodge Demon’s shatter their differentials at the drag strip and it has forced Dodge SRT to investigate and come up with a solution. We can only speculate what the solution will be, but my guess is on an official Demon Differential Brace. Here’s WHY the Demon Differentials are EXPLODING!
Drag racing puts a lot of pressure on the drivetrain. You will have some kind of issue at some point. They might have designed this car for the drag strip, but they did not build it for the drag strip.
Although Dodge’s new street legal purpose built Demon was intended for the drag strip, evidence shows otherwise. The differentials are not strong enough to handle the 840 horses the car produces when the ECU is flashed and the high octane fuel is used.
The problems with the stock Dodge Demons are more concerning. The owner in the video was staging on the line using the car’s transbrake feature, which involves keeping your foot planted on the throttle and holding the vehicle with one of the steering wheel shift paddles. As he was set, the system reportedly went into limp mode briefly before reactivating. Seeing it come back online with the throttle still pinned, he decided it was OK to launch. It was not.
Mass pointed out that at any racing event, you’re going to have at least one or two outliers that suffer some sort of catastrophic failure. It’s just the nature of the game. But he also noticed something important as the Dodge Demon underwent testing: Cars that ran full-strength passes on lower-traction surfaces were more likely to break when they returned to perfectly-treated pavement delivering maximum grip.
There are a number of reasons why that could happen. Mass hypothesizes that the wheel and tire shake generated when launching on a less-than-ideal surface is causing microscopic stress fractures in the rear differential. Put that car back on a sticky surface that doesn’t allow wheel spin or hop to dissipate any power, and the weakened structure suddenly experiences the full force of the launch.
“Our job is to prep the surface to the maximum that it can be, which exposes the weak points. That’s why Dodge brought us in for testing,” he said. “The Demon powertrain itself is bulletproof… but we did see if the car saw some prior trauma from a rougher launch, we would see part failures [on our treated surface].”
So, boom goes the diff. Mass thinks it’s likely that the broken cars in Houston had previously been used on drag strips with a lower level of preparation, generating those tiny, fatal cracks in the drivetrain that revealed themselves on his ultra-grippy surface. Short of a final answer from Dodge’s own investigation, that seems as likely a cause as anything. It certainly makes more sense than random chance or a systemic manufacturing defect on such a crucial part suddenly rearing its head.
And while the Dodge Challenger SRT Demon is surely a mechanical marvel, science can only do so much to contain the pure force pouring forth from that titanic supercharged V-8. Dodge itself advises owners to ease out of the warm-up line-lock burnout, because popping off the throttle can cause the softened tires to hook up instantly and snap something in the drivetrain. Other owners of stock models have found that the wrong combination of tires and track prep can also provoke a failure. You can’t engineer for everything at this level.
Though if it turns out that every Demon is especially susceptible to low-traction stress, that would be a much bigger problem for Dodge, one that might indeed be remedied by adding a differential brace. It wouldn’t cost Fiat-Chrysler too much to whip one up for all 3,300 cars out there. As to other fixes, well, the Demon is already out of production. An easier but possibly more expensive route would be to extend or expand the drivetrain warranty in some way.
So overall, this video doesn’t prove that the Dodge Challenger SRT Demon is doomed. But it does show that like any high-performance car, it’s only as good as the stage on which it performs—which can enhance its strengths, worsen its weaknesses, or cast a harsh spotlight on the growing gap between the two.