I think the question was C8.25 27-spline vs D35. The answer is, the C8.25 stock shafts are probably weaker than the stock D35 shafts. Because they're smaller.

 

No the 8.25 is stronger than the D35. The axle shaft diameter isn't the only thing that should be considered when comparing axle strength.
The C/8.25 has a 8.25 inch diameter ring gear, the D35 is 7.56, advantage C/8.25. The D/35 pinion shaft diameter is 1.376 inch diameter, the C/8.25 has a pinion shaft diameter of 1.626, advantage C/8.25 and the axle tubes for the C/8.25 have a 1/2 inch larger diameter, all of these things add to the strength of the C/8.25 by making gear deflection less likely, and gear deflection is a major cause of axle shaft breakage.

 

He was talking about the 27spl not the 29spl.

 

im just going to upgrade the 27 spl to the 29 spl when rebuilding. a few people have done it so i'll post up a vid when im done

 

If all of this is true, wouldn't adding a truss to the D35 correct most of it's problems?

I have 2 8.25's, out of 96 XJ's, and plan to use one to replace my D35.

 

No. You're still running weaker internals with a D35.

It all comes down to a couple of points:

1) out of the D35, C8.25-27, C8.25-29 and D44, the D35 is the weakest. Period.

2) How much money are you willing to put into something that is the most inferior of the options? A C8.25-29 is going for, what? $150-200? Maybe?

Now, you could put money into your D35 and beef it up but by the time you're done you probably could have gotten a C8.25-29 with not as much aftermarket on it but you'll have a stronger starting point.

3) it depends on what tire size and gears you are running. 31s or 32s on stock 3.55s are ok but 4.10s would be better. 33s or 35s on 4.10s or 4.56s are ok too. but if you decide to run 37's on 3.55s you might want to reconsider.

4) it also depends on how you wheel. Axle shafts tend to start breaking when the driver stops using common sense and just keep adding more right foot.

For example, everyone's seen at least one vid of someone trying to climb a step or a rock or get out of a stuck where the jeep, buggy, truggy, etc. starts hopping and bucking. this is when you need to get off of the gas. The bouncing repeatedly shockloads the powertrain and if you don't snap an axleshaft, you'll blow a u-joint, or break something internal in your tranny or TC instead.

ESPECIALLY if you're running big rubber and too tall (read: stock) gears.

5) The greater issue with the D35 (and it applies to the C8.25s as well) is the fact that the shafts are held in by c-clips. This is not a strength issue since i have yet to hear of someone breaking a shaft at the C-clip. The issue is that if you break a shaft, there's nothing left to hold the outer part of the broken shaft (and your wheel) in the axle housing. The whole assembly will walk out of the housing until it falls out. Which really, really sucks because trying to MacGyver a way to hold the wheel in place while still allowing it to turn is a *****.

If you convert your rear brakes to discs you'll have better luck because the caliper will keep the broken shaft and wheel in place. But because it wasn't designed to have to handle lateral loads you'll have to go slow and easy.


Personally, I think D35s get a bad rap. I ran a D35 with ARB, 4:10s, 32's and stock shafts for years on my YJ. Never had an issue. Never even really thought about breaking shafts TBH. But I don't subscribe to the "if you get stuck, use your right foot more" technique of offroading.

 

Good thing I was clearly only comparing axle shafts.

 

Sorry, not sure how you can compare only axle shafts unless you are comparing shafts in the same differential. As in a Dana 30 with 27 spline shafts versus 30 spline shafts, or a C/8.25 with 27 spline shafts against 29 spline shafts.
It is like comparing apples to oranges, as they say.

Mr White, nothing I stated has anything to do with whether the differential has 27 or 29 spline shafts.

alnielsen, It is all true, and yes adding a truss would help, but not totally cure the problems of a smaller Ring and Pinion, especially with gears in the 4.56-4.88 range.

 

Dude, you're reaching now. I was very clear.

 

so if i upgrade my c8.25-27 to a 29 would i be fine with 4.56 gears and 33's?

 

Sorry, dude like I stated you can not just compare axle shafts. Comparing shafts from different differentials will not give you a true measurement of the strength or weakness of the shaft in the vehicle. If you just want to make a statement then yes you were very clear, it makes no sense, but it was clear.

 

Yes, I upgraded my 27 spline C//8.25, I installed 29 spline 1541H shafts, 4.88 gears, and a Detroit locker for strength. I'm running 35s with a 5 speed and it works great.

 

Whatever dude.

 

I ****ed up the quote. That wasn't for you, but for a previous post in the thread.

 

Yes. So long as you don't beat the crap out of your XJ all of the time.

Just some of the time is ok though.