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Sheared Driveshaft

4K views 45 replies 8 participants last post by  Redtruck-VA 
#1 ·
Hey all, I have a 3rd Gen 1500 hemi mildly supercharged pushing ~500hp. Have probably 20 passes down the strip with it. Just had my stock rear driveshaft shear in half right down the middle @ 90 mph (4000 ish shaft rpm). What a mess, just crossing my fingers my tranny made it out okay. Trying to figure out what went wrong as it seems like a rare failure after talking around. Little nervous to take it out again, albeit next time will be with a built driveshaft. Since it didn’t fail in a dig from a dead stop I don’t think it was over torqued. I recently lowered the truck, which messed up my driveshaft angles. The best setup I could settle on had the tranny lifted to 3 degree down and diff at 0.5 degree up. So they are slightly out of sync at rest but this was all I could achieve to get some sort of negative working angle on the rear pinion to account for axle wrap. The truck didn’t vibrate at speed, but perhaps this mismatch still caused my failure? Did I overspin the stock shaft? Or just too much power?? Doesn’t seem like upgraded driveshafts are a hot topic in the ram performance world so any insight would be appreciated.
 
#37 ·
Looks good. Should hold anything you throw at it.
 
#43 ·
Each shaft material has pro & con to them. Steel (DOM), is tough and least expensive. Chromoly seamless tubing is a upgrade from steel. Aluminum 3.5"x.125" strong, can be made longer, operate smoother, with higher critical speed. CF is the safest, expensive, smooth operating, very strong and lightest. Recommend talking to a professional.
 
#45 ·
the main advantage of an Alum driveshaft for a QC ,it's easier to balance for the length and if it does flex, it will return to shape better than a steel shaft.
the Carbon Shafts should be left on the track, you get enough stone chips in them and they'll let go.
 
#46 ·
In a failure, a cf shaft unravels and dissipates it's energy in small pieces causing least amount of damage. Aluminum and steel releases its energy in large pieces with the same mass as the original shaft. Smaller diameter shafts reach critical speed at lower rpms than larger diameter shafts. Heavier the shaft material the more likely the shafts harmonics will be more distructive. Ideally for me, I would use a cf shaft for racing and an aluminum for street.
 
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