31 spline axle upgrade- What is necessary

[Ace23]

For those of you who have performed a 31 spline axle upgrade is their a link or a previous thread that list the required components? We plan on removing the rear end for a gear upgrade and really wanted to get a head start on sourcing the components. At the end of the day I'm sure the best thing to to is to take it apart piece by piece but I wanted to give this a shot first. My car uses the 8.8 rear end. Below i what I have purchased.

*Motive rear gears

*31 spline Eaton Tru-Trac Diff

*the rear end rebuild kit from Ford.

*I have contacted the Drive Shaft shop for the 31 spline axles.

[LMH]

I'm not an expert on SPF but have done this on my Hurricane. The hard part to source was the CV joint which is what's 31 splines. At the time, Ford didn't seem to be making them and I had to buy a set on eBay from a Mustang. Once I had those, I sent them to DSS and they rebuilt them and added their 300M center shafts. Super strong!
Larry

[Ace23]

Originally Posted by LMH

I'm not an expert on SPF but have done this on my Hurricane. The hard part to source was the CV joint which is what's 31 splines. At the time, Ford didn't seem to be making them and I had to buy a set on eBay from a Mustang. Once I had those, I sent them to DSS and they rebuilt them and added their 300M center shafts. Super strong!
Larry

Larry,
Thanks for the info.

[LMH]

I see companies like G-Force now make the stub axle. Pricey but at least there's a source besides the 03-04 Mustang GT.
Larry

[vatdevil]

Upgraded car 522 with factory new 03-04 halfshafts, replacing the bars with DSS 4340.

[vatdevil]

http://www.clubcobra.com/forums/supe...de#post1288675

[Ace23]

Originally Posted by vatdevil

http://www.clubcobra.com/forums/supe...de#post1288675

Can you recall the process of pulling the rear diff? We plan to change the rear gears and have the diff and axles replaced with the 31 spline setup. The rear ended of the car is the only portion we have never torn apart.....any assistance anyone can lend on what is or is not necessary to remove would be excellent.
Thanks

[LMH]

Best have an SPF expert answer the specifics of that one. I've never taken an SPF differential out. Mine just unbolts, two in the front and two in the rear. That's after pulling the axles out of course.
Might look at a high strength cover for the back of the differential while it's out. The production cover is very weak, so easy to change while it's apart.
Larry

[Jim Vander Wal]

This is from memory, did it back in 2005.

Disconnect the drive shaft.

Pull the top bolts on the spindles. Pivot these outward. During this process you'll need to pry the inner CV axles out of the diff case. Big screwdrivers seemed to work well. Just get them out of the way.

Don't stretch out the boots too much, they are the only thing holding the CV assemblies together.

Unbolt the 4 (?) bolts holding the diff case in place. They are obvious and not hidden. It will start to drop during this process. Support it somehow while you're unbolting and lowering it. Weighs 80-100 pounds.

You're done. It's easy on the Ford 8.8 IRS units. The newer Dana units are problem.

FYI, in 55,000 miles I never broke a 28 spline axle. Tore boots, trashed CVs, wore out tires and brakes, sucked up a lot of gas, got real wet many times, went fast, went quick but never broke an axle. About the only ones I know of that broke were drag racers running slicks. The 31 spline system is a good upgrade, I just don't know if it's necessary.

Jim

[Ace23]

Originally Posted by LMH

Best have an SPF expert answer the specifics of that one. I've never taken an SPF differential out. Mine just unbolts, two in the front and two in the rear. That's after pulling the axles out of course.
Might look at a high strength cover for the back of the differential while it's out. The production cover is very weak, so easy to change while it's apart.
Larry

Great idea on the cover. At this point what's another $200.

Originally Posted by Jim Vander Wal

This is from memory, did it back in 2005.

Disconnect the drive shaft.

Pull the top bolts on the spindles. Pivot these outward. During this process you'll need to pry the inner CV axles out of the diff case. Big screwdrivers seemed to work well. Just get them out of the way.

Don't stretch out the boots too much, they are the only thing holding the CV assemblies together.

Unbolt the 4 (?) bolts holding the diff case in place. They are obvious and not hidden. It will start to drop during this process. Support it somehow while you're unbolting and lowering it. Weighs 80-100 pounds.

You're done. It's easy on the Ford 8.8 IRS units. The newer Dana units are problem.

FYI, in 55,000 miles I never broke a 28 spline axle. Tore boots, trashed CVs, wore out tires and brakes, sucked up a lot of gas, got real wet many times, went fast, went quick but never broke an axle. About the only ones I know of that broke were drag racers running slicks. The 31 spline system is a good upgrade, I just don't know if it's necessary.

Jim

Jim thanks for the details. We considered not doing the 31 spline upgrade but with going to a more aggressive rear gear and running drag radials I thought it was good insurance.... I don't drag the car at all but it will be good to know it's not a weak point in the car.

[Inertia]

Originally Posted by Jim Vander Wal

Tore boots, trashed CVs, wore out tires and brakes, sucked up a lot of gas, got real wet many times, went fast, went quick but never broke an axle.
Jim

Hi Jim, did you upgrade the CVs when they failed and if so what to?
Cheers
Steve

[Jim Vander Wal]

Steve,
Got rebuilt axle assemblies for a T-Bird Super Coupe from NAPA. Pushed out the axles and used the inner or outer CV assemblies as required. Used a hydraulic press to separate the pieces.
I never upgraded, many friends went to the 31 spline diff and CV assemblies. The fancy parts get expensive.
Jim

[Inertia]

Thanks Jim,
I reckon I will take your advice as fancy parts are to the power of 3 over here in Oz.
Cheers
Steve