I have a 78 ford f-150 with a 9" and 31 spline axles, I was looking to upgrade to a powertrax locker and was wondering if I could just upgrade the axles with it to a 35 spline. Is this all I need or do I need to look at getting a third member, ect. Thanks.

Pretty sure you need an aftermarket 3rd to fit the larger bearings used with the 35 spline carrier.

Pretty sure you need an aftermarket 3rd to fit the larger bearings used with the 35 spline carrier.

The way I understand it, too...

I've been told there are some odd ball bearing that will work with a stock third but they are kind of on the thin side. If you are going through the effort to go to 35 spline axles you will want to upgrade the third member anyhow. The after market third members are stronger around the inner pinion bearing and thats what usually breaks on the stock third members.

I've been told there are some odd ball bearing that will work with a stock third but they are kind of on the thin side. If you are going through the effort to go to 35 spline axles you will want to upgrade the third member anyhow. The after market third members are stronger around the inner pinion bearing and thats what usually breaks on the stock third members.

Yes, but like you said the stock third is barely strong enough to hold up to 31 spline shafts let alone 35....

So get a 3.25" race case for under $300 and load it with all the goodies you want. I say race because it's stronger than the street version.

Best OEM is good for 400 horse
street case is good for 600 horse
race case is good for 1000 horse

Obviously it's the torque that kills them for us and not the hp....

If your gonna go thru all that trouble....do a Currie Hi9

why dont you wait and see if your gonna break it first w/ stock shit?


i have BEAT on my 31spline 9 inch w/ 38" boggers, nitrous, burnouts, comps and daily driving........


been thru a few ring'n'pinions and one or two center sections, but no axles yet....
i do need to replace a fuggin axle seal again though :mad3: