[Azathoth]

What gears are you using? (not sure if darklen was actually telling) If it's ACM stuff like 5KU, SHS, ELement, Supershooter that is probably a big factor. I never had a problem with systema helical torque. If it's helicals and they are not shimmed correctly that is likely culprit

If you are running Guarder, Systema, Prometheus Modify gears than the culprit is likely god awful shimming. And I mean really god awful.

We need more information to diagnose the issue. If you have a terrible E1 or G&G gearbox shell it may not be built to the spec or warped / misshaped. Bad bearings/ improperly seated bushings can also be the issue. I ONLY use TM, Systema, G&P gearbox shells. I've heard that KWA shells are also excellent Avoid Modify Taurus unless you are using a completely modify build. Other brands shells are often not built to the correct specs most importantly the axle holes are not centered correctly (see airsoftmechanics). I had this problem with a G&G cansoft shell.

Where are the gears shredding/failing? What brand is EVERYTHING inside the gearbox.

Send it my way there is no reason why you shouldn't have a v2 gearbox that fits those specs. BTW what is the definition of "HIGH ROF"? Are we talking 70+ or what?