Re: 49 Axle shaft

Posted by Peter Packard On 2014/2/4 4:10:14

I would suggest that you do not change from 4.1 to 3.9 unless all of your travels are on the plains of America. Your 4.1 when put into overdrive is 28.7% overdrive and the difference in conversion to 3.9 will be less than 100 rpm. If you convert to the 3.9 before overdrive, you risk being a bit more overdriven on reasonable hill climbs and you will be "kicking out" of OD more often. I have learned from bitter experience that perhaps the Packard engineers knew their Onions. Damaged axle shaft change...yes....Diff ratio change from 4.1 to 3.9 ...very debateable. But it is your car ..so whatever you want is of course approved. Best Regards from Down Under where my locality has just enjoyed ( endured?) its' first week of over 100F for 125 years. My Packards did not overheat in this...phew!. PT