I'm going to be changing the fluid in my diffs. I have only one real question. Why, when ever I search and find torque specs for the the diff cover bolts its 29-39 ft lb torque? To me thats quite a spread in a tolerance.

Are these numbers right? And should I just split the difference?

I'm kind of afraid to max torque to 39 and force the silicone to thin? Is this a worry I should be having?

 

The high is so you don't break the bolts and the low so they don't loosen. The silicon won't be too thin at 39. As long as you keep the torque between those, you'll be alright.