Originally Posted by Miami_Son

I suggest a torque wrench for anyone new to working on their car, regardless of the part. I rarely use a torque wrench except on things like heads, pinion nuts or other critical parts subjected to heat/cool cycles that depend on proper torque. But I have years of experience in working on vehicles and have pretty good feel for when a fastener is properly tightened. Someone new to this probably doesn't and that inexperience can lead to everything I listed earlier. In the case of a diff cover, they are so thick that they're pretty hard to warp from over-tightening, but you have to consider that a leak from even a small warpage will likely go unnoticed and could cause all the fluid to eventually leak out over time. And undertightening can lead to fastener loss, also easy to go undetected under the vehicle.

When I had my Harley shop I regularly saw the damage that can be done by some DIYer who thought damn tight was the right torque spec.