NV5600 Torque Rating

[rbattelle]

Please excuse me if this has been covered before...



According to the NVG website:



http://www.newventuregear.com/transmissions.html



the 5600 is rated only to 550 ft-lbs.



Now, I know Dodge did not over-load the transmission. But why the discrepancy? What's the true input torque rating on the 5600?

 

[Wiredawg]

550 is prbably a misprint. The documentation we were given at TDR Nationals listed 600 ft lbs.



Wiredawg

 

[Pit Bull]

What did they rate them at in 02 since it's the same transmission in the 03's. Is this just marketing hype? If it is only 600 I just saw some lucky guys running on a dino recently that should have broken transmissions based on their dino runs

 

[krabman]

The limit is because of the clutch.

 

[Pit Bull]

Originally posted by krabman

The limit is because of the clutch.

Thanks Krabman, that makes sense.

 

[Gary - K7GLD]

I seriously doubt the clutch used in various applications has any great impact upon ratings NV places on the 5600 - but I *do* suspect the rating NV uses is based upon some specific percentage of time vs load - say 550 ft lbs applied 60% of the design lifespan of the transmission - certainly, it is NOT a one-time maximum peak rating! Shucks, my own truck dyno'd 656 ft lbs at the REAR WHEELS, and has pulled a number of decent grades with a heavy foot towing our 5er and Comp on 5x5...

 

[Wiredawg]

I believe it is the clutch as the limiting factor. I read somewhere a few years ago the transmission is actually rated at 1,000 ft lbs, but officially, the literature I have says 600 ft lbs. Since my 00 2500 dyno'd 774 ft lbs of tq and I had the original clutch, I'd say the transmission can take it.



Wiredawg

 

[Gary - K7GLD]

The point I was trying to make (poorly) was that NV does not supply the clutch, and has NO WAY of even knowing what size/type clutch will be used - so it would be both difficult AND impractiacal for THEM to apply a spec related to a condition about which they have no knowledge or control!



They *DO* know what the part THEY supply (the transmission!) is designed for, and THAT they CAN supply figures for... NOW, IF NV supplied the transmission AND clutch assembly as a UNIT, THEN that clutch argument might hold some water...



But as far as *I* know, they don't...



Do they?



(Dern, I *hate it* when I stick my neck out!)

 

[RSnaith]

That rating that NV has isn't all that useful, without telling you what it is. I suspect its probably shear force in direct drive though. IE) holding the output shaft rigid, you can apply 550 lbft of torque to the input before breaking something. This is really the only true test of a transmission, as its ability to handle a torque load in a vehicle will be highly variable based on vehicle weight, SRW or DRW, and axle ratio.

 

[jimnance]

I wouldn't be suprised if this is design load as opposed to ultimate load. Design load is probably conservative and as someone else suggested is based on some calculation involving expected life of the component in conjunction with the percentage of time at 100% rating.



Just a guess, but we all know it can take a lot more - at least in the short term.

 

[D808]

I believe that the overdrive gearing is the weakest link in a transmission. If that is true, wouldn't the maximum torque rating be most applicable to overdrive operation?



Federal Man

 

[krabman]

Often my responses suffer from brevity. Some years ago during a repower (399 to 3516, 1200 to 1800 hp) we had the guys from falk down to take care of the reduction gear portion of the job. They pulled the plate (seriel number/product id plate)off the side of the reduction gear and swapped it with one with a new max hp rating that was coincidently 40 hp more than the 3516. That was it. We of course also repitched the wheel now that our newly buffed up gear could handle the extra prop. I have seen this kind of thing many times. A lot goes into such a rating and much of it has little to do with what the equipment can actually handle. If you think DC didnt have any input on where that rating would end up your kidding yourself. I wouldnt be suprised to see a little bump in power soon in response to the new powerstroke and I think you will see a new max rating but no new part numbers on that box. Its not exactly a secret that it can handle more power reliably.