700r4 Real axle ratio

Posted by Mathew Rattray On 2015/3/28 4:41:32

Hi All,

Down here in Australia we have enjoyed our national Packard Rally in the Hawkesbury, NSW. It was a great rally and my 1955 Packard went very well with the 700r4 transmission. This is defiantly a much better gear box than the torqueflite 727.

The only issue I have at the moment with the car is a noisy differential. It whines quite loud so I will be looking at getting this sorted soon. When I purchased the my Caribbean it has a manual transmission in it. From what I recall the car currently has a 3.54 ratio diff in it. This was probably put in to work with the manual box. Considering I now have a new gearbox installed it might be worth putting in a higher ratio diff. I was wondering if others out there with the 700r4 conversion have made changes to their diff gearing, and if so what are you running and what would you recommend. Would it be beneficial to change to a 3.07 or go lower or higher?

Many thanks,
Mathew