Out of a 28, 31, and 35 spline axle shaft, which one would be the strongest? The one with more splines or less splines



1978 F-150 flareside. Primitive by todays standards but she was a jaw dropper back then. :-staun

 

More is better! But really, it's completely possible to get an aftermarket 28 spline that's stronger than a stock 31. Overall, more splines, larger diameter shaft, larger is stronger. Ford never made a 35 spline, the bearings for the axleshafts require a 3.250" bore to seat in (2" bearing), larger than stock. This would require an aftermarket (stronger) case. I think Ford Motorsport has 'em as well as Strange. You may be able to take a stock case this large, but it would be severely weakened, thus defeating the purpose of 35 spline axles! I think the only choices for the 35 spline are a spool or Detroit Locker, old style-not the "soft-lock" which most are these days.

 

I think I read in the recent past that the 28 was stronger and was made in the early years.If I can verify this Ill let you know.

 

Nope, the 35 spline is the strongest due to its largest diameter. The diameter is what its all about, not the splines. For example, the Dana 60 came in a 16 spline variety in its earlier incarnations, which is every bit as strong as the 28.

 

That's what I thought (about the 35 spline being stronger). Seems like I remember reading in one of magazines a while back that they were more durable then the 31 and 28. I went to the salvage yard last week to inquire about a 9" rear. Didn't matter what ratio and when the guy asked me what spline I said, "It doesn't matter I'll be swapping 35 spline axle shafts into it in the future anyways." He looked at me funny and said, "But they already have 31 splines in them." I thought "No S---t shirlock, that's what's in the rear end I have now." And kept telling me this THREE times. To be quiet honest he got on my nerves real and I said look...can you find me a rear end or what?? I think that got him mad and gave me a price of $400+-. I said ok...thank you and left. I don't think I'll be back there anytime soon with his attitude. I just wanted some clairification about the strengths of the three just to be sure. Why should it matter to him what I plan to do with it anyways??? It's not his truck or money.


1978 F-150 flareside. Primitive by todays standards but she was a jaw dropper back then. :-staun

 

On the Moser Engineering website they list the comparative strengths of different spline axles and have a calculator to figure out the axle size you need based on engine torque and gearing.But diameter is the key as I had a set of 31 spline tapered bearing truck axles next to my 31 spline passenger car ones and the truck ones were much larger everywhere except at the splines.

 

 

The center section (pumpkin) you use has to recieve the axles and the number of splines has to match. You cannot change the number of splines on the axle without changing the carrier to match. Ford made both 28 and 31 spline axles, 35 splines are aftermarket and you will have to use an aftermarket differencial to match.

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