Re: Severe diff noise

Posted by Tim Cole On 2012/5/3 16:59:46

Dear africapackard:

Loose pinion nuts are something I never see so I wonder just what caused the problem.

What the manual is talking about is Pinion Turning Torque to Rotate. That requires a special inlbs torque wrench and a special plate wrench to hold the flange.

The procedure is to carefully tighten the pinion nut until the torque required to keep the shaft turning is in the specified range. With the differential gears removed.

When servicing the pinion seal the minimum required is to remove both brake drums and preferably both axles and measure the Total Torque to Rotate using the inlbs wrench. Then reinstall the nut and very carefully tighten until the Total Torque to Rotate begins to increase above the starting point. That sets up the preload for the pinion bearings.

But given your situation has no starting point this is not possible so let me give you some specs from the DANA Axle manual which are similar to Packard except Packard didn't use Total Torque to Rotate. They used a dialed in differential preload method which I use today as well and requires some special tools.

Now Dana typically calls for Total Torque to Rotate of 7-11 inlbs above the Pinion Torque to Rotate for old bearings of 10-20 inlbs. So pull both axles and shoot for the 24 inlbs that Packard specified for new pinion bearings.

But be careful because if the differential is in the same shape as your pinion then you could go too far. If your differential is still noisey then it has probably been damaged.

As for threadlocker - blue should be fine, but red requires heat to remove.

Good luck with your car.

PS: this is all very technical and the common method is to just air wrench everything together and hope for the best.