Torque for getting a load started depends on transmission ratio and axle gears (and tire size).
If your new transmission has a lower first gear than your current that helps, if not then it's the same or hurts.

Your axle gear ratio isn't 1.5, not an option. More than likely it's around 3.00. In jacking up ONE wheel turning it and counting drivehsaft turns you need to use a factor of 2 in your calculation. With one wheel standing still the other turns twice as fast due to the differential gears.
I suggest you turn only one wheel 20 times. Count the driveshaft turns and divide the number by 10 for your answer. More turns in your calculation gives better accuracy.

Grigg


•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-