Gear whine after fresh install

[Christian Cornwell]

So Ive been working on installing a new set of Ford racing 3.73s. I've installed all new bearings, races and rebuilt the traction Lok while in there. I set the backlash with a magnetic dial indicator and put everything back tother. After getting the car together I took it out for a drive and noticed pretty bad gear whine when letting off the throttle. I only drove the car about 5 miles. I pulled the cover off and backlash was good and I checked the gear mesh and it looks something like one of these two

Now it more resembles the top one to me so I pulled the pinion out and this is what it looks like.

I assumed after checking the gear mesh that it needed another pinion shim but now after seeing this it makes me wonder. I though the backlash might have been a hair right when I put it together at about .008 so it doesn't seem like I should decrease it any like the above picture says. Just wondering what everyone's thoughts were. It also doesn't look like the pinon crush spacer has been crushed even a drop. It seemed like I was at the right amount of turning resistance with the inch pound torque wrench but maybe that needs to be tightened a little more. I was pulling on the 3/4 rachet about as hard as my skinny a$$ can but maybe it still needs more.

Just curious what everyone thinks. Not too sure on what to do just yet but know that I don't want the gear whine.

 

[Neuron]

Found this:

Re: pinion nut torque spec?

The Pinion Preload is the rotational torque you would get if you placed a dial Indicating Inch pound torque wrench on the pinion nut and turned it without the carrier installed, it measures the free rotational force required to turn the assembled pinion gear and is required so your Pinion bearings will fully seated and prevents them from being too loose. I wouldnever go by the set torque they give you for the pinion nut as it is the required torque to crush the collar only. I get the collar crushed using the above method(old nut used) and then afterwards it's easier to turn and tighten. Afte that I take carefull turns on it until I start to feel the pinion seating in the bearings, then I take 1/8-1/16 turns, alternately checking with the Dial indicating Inch pound torque wrench for the correct preload. Hope this helps clear some stuff up.
BTW, I always use either Automatic Trans Assembly grease that disolves in oil or plenty of Gear lube for preassembly, never assemble the bearings dry as when you try and do the preload you will get false reading and probably damage the bearings.​

 

[Christian Cornwell]

The way you described for setting preload is the exact way you described.

I did however figure out what the problem was. I believe the problem was a combination of not enough pinion preload and the carrier not being snug enough. After putting some more preload on the pinion and adding 4 more shims I've got the gear whine completely eliminated and the gear mesh looking much much better. However I do have a strange vibration at 60 that wasn't there before. Guess I'll be working on it some more tonight.