8.25" upgrade

What would be needed to upgrade a 27 spline 8.25” axle to a 29 spline axle? I know new shafts and a carrier would be need but is there anything else or is this impossible due to some other issue.

I would go to the junk yard and see if they have the spline that you are looking for. That way you are ahead. Then over time save for alloy shafts and a locker. Do it right the first time.

OR

Do what you are talking about. I would invest in a seal kit as well as some bearings and update the entire setup.

Do you already have the 8.25? If so, its really that simple. If you do not already have it, get a Ford 8.8 as it is stronger and it has disc brakes.

Your call? Let us know what YOU decide?

The 27 spline axle is stock on my '92 jeep, so I was looking for upgrades for that axle. I had also thought about getting disc brakes from a grand cherokee as an upgrade also.

I also have the 27 spine axles, and what I'd like to know is, in reality, how much stronger will two splines make the axle. I don't care about anyones anectotal "evidence". I wanna know REAL numbers. Will two splines really be worth the money and hassle? Does anyone have any real numbers to compare the two (i.e. load and shock ratings)?

I get the impression from some that I've spoken to that most people think the 27spline 8.25 is so weak because they equate it with the 27spline D35 which everyone KNOWS is weak, when in reality there's no comparison between the two.

If someone's got some hard evidence to the contrary, then bring on the :flame:

I believe the shaft diameters are different

Dana 35 non c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 84-89

Dana 35 c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 90-01

Chrysler 8.25 - 27 spline, 1.17" diameter shafts, 8.25" ring gear, 3" axle tube - used 91-96

Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, 3" axle tube - used 97-01

Dana 44 non c-clip - 30 spline, 1.31" diameter shafts, 8.5" ring gear, 2.75" axle tube - used 87-89 on some (not all) XJs equipped with towing package.

You could calculate the increase in torsional strength.

Bainer said:

I believe the shaft diameters are different

Dana 35 non c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 84-89

Dana 35 c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 90-01

Chrysler 8.25 - 27 spline, 1.17" diameter shafts, 8.25" ring gear, 3" axle tube - used 91-96

Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, 3" axle tube - used 97-01

Dana 44 non c-clip - 30 spline, 1.31" diameter shafts, 8.5" ring gear, 2.75" axle tube - used 87-89 on some (not all) XJs equipped with towing package.

You could calculate the increase in torsional strength.

Click to expand...

Hmmm. Based on these numbers, the D35 shafts should be stronger than the 27spline 8.25. Bummer. I realize that the axle tubes are bigger in the 8.25 which will make the overall axle assembly more stout.
I'm not an engineer so I couldn't begin to calculate the differences in torsional strength. Even if I were, do all use the same steel alloy? Made by the same mfg with the same processes?
As for the 27 vs 29 spline 8.25, how much stronger will a .04" difference in diameter really make?