How critical is torque

I just completed the 30k oil change in the front and rear diff; and the transfer case. I purchased a torque wrench for the job but I think it failed so I am not sure what torque I applied to all of the drain and fill plugs. One I am sure I over-torqued because the washer became enlongated - I replaced it and applied less torque. Final test I gave the torque wrench was to set it at 20 and apply torque to the wheel lugs - it never released. Seems that all the plugs are in tight, so what is the risk of incorrect torgue on these plugs.

 

You sure you didn't buy a torque wrench that measure inch lbs instead of ft lbs?

 

You should be fine, as long as you tightened everything down.

 

It was ft lbs - Gearhead brand purchased at Pep Boys.

 

Overtorque on the drain bolts will strip the aluminum pans/housings/covers.
Overtorque on a steel pan/housing/cover is not good, but you've got to really crank to do damage.

Lug nuts are generally around 80ft/lbs. If the wrench is set to 20, it's going to click right away and you'll never feel when you reach 80.
A click type wrench does not release at the set torque, it simply clicks and you feel it. You CAN continue to crank... the click is just to let you know when you've hit your target.
In many respects, the old beam style wrenches were more idiot-proof because you could see when you were continuing to go over... if you could see the scale, which was not always possible and the reason for the clicker's invention in the first place.


Torque is important on all fasteners.
Some of us have been wrenching for 40 years and have a good sense of feel, and rarely use a torque wrench... I know a lot of guys who can install a set of spark plugs, then a check with a torque wrench will have them within a couple of inch-pounds of spec...
but we still bring one out when working an unfamiliar system, or high-torque situations where "Oomph" is not good enough to ensure safety.

 

When you surpass the strength of the aluminum casting, or the strength of the bolt. Aluminum will be the first to go in that case, and it will strip when you have over torqued it. Probably around 10-15lbs more than is spec'd.

 

Mine was just a guess, since i have never tested the "stripping point", but that would really suck. Much worse that just stripping the threads. Yikes! Lesson to be learned there, that's for sure!

 

Not sure... I don't have a 4x4.
Easiest way to check is to see if a magnet sticks to the pan/housing, since the only thing you're going to find is steel, iron, or aluminum... maybe magnesium on a motorcycle.

 

Torque wrench time.

And set to the proper torque.

And the proper SIZE torque wrench.
A wrench that goes from 5 to 60ft/lbs is useful at neither 5-10 nor 50-60 ft/lbs... you want to be in the middle 40-60% of the range for best accuracy (and I know you know this).

I have 5 torque wrenches including one 1/4" drive for small fasteners on the motorcycle.

 

I can't remember but is it a tapered plug? If so, cracking would be a very big concern!

 

I guess I am okay, except for the black n blue finger I got from "attempting" to overtorque the transfer case drain plug.

 

Not tapered. Just a straight bolt.