[JustROLLIN]

To give you an idea what the gear differences are, look at it this way. Helical gears are cut an angles, the gears spline into each other at an angle, not directly at each other. Like this ///
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While spur gears are straight cut gears. When you back up in a manual transmission car, that noise or whine you hear, those are the spur gears singing. They meet at a straight point, versus at an angle. They tend to not be as strong as helical gears due to a single contact point.

Just more info for ya.