I have a question in respect to spline counts on axels and transmission input shafts. It seems that on axels, the more splines the better. On a transmission input shaft(manual transmission)the fewer the better. Now I'm not the brightest crayon in the box but what gives? I know that more splines means more surface area and in respect to axels larger dia. So why does it seem that there are two standards?
Just something that I have been wondering about.
Opinions.

Digger73(Mike)

I like more splines on the trans input because it makes it easier to stab in the hole (self aligns). 10-spline inputs usually require turning the output shaft to align the shaft/clutch disc.

It's a machine design thing. There are standard ratios of splines per pitch diameter. As most of the axle manufacturers use the same standard ratio (I forgot the name), on most axles the diameter of the axle is directly proportional to the spline count. So a 30 spline axle is smaller than a 35 spline axle. And because torsional strength goes up as the cube IIRC of the diameter, the 35 spline axle is much stronger.

On transmission input shafts it is again the diameter of the input shaft that matters. Here, different manufacturers use different spline counts for who knows what reason. So there are 10spline inputs in 1, 1 1/16, 1 1/8, 1 1/4, 1 3/8, etc.
Then there are the fine spline, skys the limit.

On Mopar cars the 23 spline input is smaller in diameter than the 18 spline "Hemi" input. Guess what's stronger?

R.

Fewer splines on anything that has to transmit power is probally weaker than the same diameter shaft with more splines More splines ends up having more contact surface area than fewer splines, correct?

I think the confusing issue MAY be the 18 spline vs 23 spline on the 833 input shafts. The desireability of the 18 spline lies not in the splines of the input shaft, but rather the cut of the gears and their inherent strength.

The 18 spline is just the easiest way to ID these trannys. yes? no?

The 18 spline Hemi/440 input shafts are bigger diameter than the 23 spline input shafts, I think I'll have to go measure them in the morning now to make sure

As I said above, the Hemi shafts are larger.

R.