Can a person change a 28 spline to a 31 by changinig the third member and axles in the same housing or is there more to it?

 

Basically yes you can, but you have to make sure the axles are the same length as what you remove. Not a 100% sure, but the axle bearings should be the same size. Why go to this expense in a truck?

Barry

50 F-1

 

Unless you are building SERIOUS HP the 28 spline will be good to go. A lot of effort and $$$ that could be better spent somewhere else IMO.

Ron

 

it should be as easy as that,and 30% stronger.if your 28s show wear,why not upgrade. i did the same on my 55f100 using a antique bronco housing,converted it to disc brakes and added moser 31s .also kept the truck bolt pattern.

 

Fridge -

Yes, that's exactly what I did when I changed out the rear end in my 9-inch and went to a posi. Also replaced the seals at the wheels.

NOTE: The buddy who heped me do this worked at Currie. He put a small magnet into the bottom of the case before putting in the posi. It's used to capture any gear shavings and keep them out of the gear mesh.

 

I have a 64 truck that I just put 3.25 gears 31 spline in that I'm selling. My 60 is a 28 spline with 3.89 gears. I would prefer the 3.25 in the 60. I can't change out the housing because the 64 has been lowered with more shocks and swing arms added to the housing.

 

If you are going to run the HP instead of switching to the 31 spline concider going to a 35 spline axle. New 35 spline axles with bearings and seals along with a fully loaded third member with a detroit locked and 3.25 or 3.00 gears run around $1600 from Strange. The axles are their street/strip axles and are 1 1/2" diameter axles the entire way and there third member is beefed up to handle the HP and torque too. took about 15 mins to install the axles and third member into the truck. and the guys at strange are great to work with also just tell them what you are doing and they will set you all up. and you won't have to worry about the axle again, just the drive shaft and trans as i have found out. the rear end held but the trans didn't