Ok an update. I think everyone know about my propeller shaft rebuild. I just removed it and in the process I rechecked my pinion preload.
It seems to still have preload but I also noticed that it has lost a little preload.
There is a very slight hum especially when the diff "floats", meaning when the gears are not under load, like when I am coasting downhill but I still give it very light throttle, its like the ring and pinion is under minimum load if you get what I mean. When I let go of the throttle and just let it coast there is hardly any sound. On hard acceleration, also hardly any sound. So I was wondering, should I replace this nut and just crank down on a new nut (I have a spare nut) just to get the preload tight again. I shouldn't have to worry about overtightening as there is no crush sleeve in here.
Its just difficult to tighten this nut under the car, even with my companion flange tool. I plan to rest the tool rod on the floor and tighten the center nut, but I have a feeling I would be lifting the whole chassis up a little as I crank hard on the nut.
Also I have another question. I re read the TSRM, and according to the wording
"Using a torque wrench measure the preload of the backlash between the drive pinion and ring gear"
Doesn't this mean the break away torque ?
If that is the case then I probably have the pinion preload a bit too high ?

Also notice the illustration shows him checking the torque under the car, meaning it cannot be a constant turning torque.
Another post by turbostreetcar:
