The Stovebolt Site Forums The Shop Area Driveline rear axle ratio

Hello folks,

Hav'nt been on here in several months, I usually get my answers just grazing around this forum. I've been meaning to check the rear axle ratio on my 283 65 custom deluxe C-10 long bed for a while because I'm fixing to have the engine rebuilt and also put a Hurst tremec 5 or 6 speed in it. The numbers on my axle are not on the tube, they are on the rim of the housing, C0N3, 67890, and A81. Could not find them anywhere on any chevy charts, the axle was changed out about 4 years ago due to updating my brakes. This morning I did the turn the tire and watch the axle spin test and got a ratio number that I have never seen before. It is 1.50:1. Yes the axle turns only one and one half rotations per one complete tire rotation. My tires are 28 !/2 inches tall. I don't have to tell you that I have very little torque ( it will barely move an empty 16 ft. trailer) but you can fly down the highway. Am I going to have to change out this axle yet again, because I need to pull my trailers occasionally. I've been using my wive's Nissan Frontier every time I need my trailers. Will I have much more torque with the new hurst 5 sp. tremec trans and my same axle.?

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

Thanks Grigg,

I don't remember reading about the 2 factor, that should be a lot better. I left my truck up on my jack stands. Both wheels are up. When I turned the wheels with both wheels free, the axle would turn slightly and then just quit turning, so I stopped one wheel and did the test turning the axle several times getting the 1.50 ratio, so I just double that and I have it. I'll also check it again later. Thanks a lot, I really appreciate your help. So, the weakness in pulling may not be a torque issue, it may be from lost hp in the engine, like I said, it needs rebuilding, black oil coming out of passenger side tail pipe.

Again,
Thanks alot
Joseph