I read lots of good review for 4.8 final drive , but not so much regarding the kit from AUTO FACTORY , wonder does any one have negative feedback for this kit. I heard about like kit from Mfactory might cause some strange noise. But not sure about AUTO FACTORY.

The Auto Factory final drive kit uses an OEM Toyota gear, so it shouldn't make any noise.

MFactory kits may have some gear noise because they're semi-helical cut.

For reference:

• OEM gears are helical cut, which are quiet, but less efficient (more drivetrain loss).
• Straight-cut gears are opposite; most efficient, but most noisy (typically used on dedicated race cars).
• MFactory gears were designed to be kind of in-between.