You ought to rethink this.

The 2.88 gets the 617 down to a much more comfortable rpm at 70 mph. Also, the fuel economy with the 2.88 is improved by a few percent. It's defiinitely the preferred diff for the vehicle.......unless you choose the much taller 2.47.

I had the exact same issue with the pinion whine and switched the SD to a 2.88 and can't be more satisfied with it. It is limited on its hill climbing capabilites, however..........65 mph is about it on most decent grades.

Get the complete setup from Jack. It's definitely worth the additional cost and the fuel savings over time will pay for the cost of the parts.