I've been browsing these forums for a couple weeks now, and one thing I've noticed is there doesn't seem to be a definitive/well-collected opinion on output shafts, whether stock, aftermarket, 2WD or 4WD. If there is a good thread about this, I'd love for someone to direct me there, but otherwise, what are the stock shafts rated to? What have people experienced as far as failures? This is including aftermarket shafts, if you've managed to break those.

 

2wd shafts are all stronger than the 4wd shafts.
That's because it's longer and gets more "twist" to spring back from

There are "rings" as identifiers on the HD shafts which would be from 4l65 and 4l70 stuff
I think @PBA or @FranksCustomTrans might have that info off the top of their head.
I'm away from the shop and my notes but if they don't get back to anybody here before next week I can update.

As for a HP level when/where they might break...that's a crap shoot.
I've had some break around 500
I have other customers with nitrous TBSS making over 700hp at full weight on stock and it's fine

I think in a large majority of cases, 700+ is no problem for them.
If you do break one, just pony up and buy the sonnax shaft if you can find one in stock.

 

I don't expect my car to exceed 700hp. I'm certainly aware that vehicle weight and 2 vs 4WD makes a difference, but that's interesting to hear the 4WD is "weaker". It does make sense though, thinking about it. I just figured 4WD broke because of the extra traction. Since my unit is a 4WD, I'll need to know what 2WD shaft to put in. I work at a transmission shop so we've got a few shafts laying around xD

 

The identifiers MaroonMonster is referring to is at the very end of the shaft. There are 3 lines and 6 line output shafts. The 3 line are HD hardened shafts, the 6 lines are not. But, you can take a 6 line shaft and Cryo treat it to help make it stronger. But, do not Cryo a 3 line as it will make it brittle.

This information was from PBA that he shared with us in one or two threads prior.

 

I'm not surprised that we don't have any 3 line shafts on our shelf, if they're all from 65/70e units. We don't really have any cores of those laying around. I'm weighing whether I need to get a shaft from sonnax or just do like MaroonMonster says and build it, and if it breaks go for the Sonnax. If I wasn't building a street/strip car, I'd just leave the shaft alone as I have never seen a 2WD shaft break from torque. Only one that was broken is because a U-Joint gave and the driveshaft snapped the back housing in two

 

Most failures are from wheel hop or similar shock loading of the input shaft. So keep your vehicle from doing that and your chances at your power level will be just fine

 

Is that even with a 6 line shaft? Should I bother cryo-treating or just let it ride?

 

In my general experience , Broken output shafts are ussually from an external cause like maroonmonsterLS1 mentions, I have seen many stock shafts hold up just fine at 700 800 rwhp. As long as the shifts not to crazy (many try and see just how hard they can make it shift) I would just go with it and use it,
If I was going to spend money it would be on the input side though even then the drum is more likely to give before the shaft. But again depends on the trans build itself how aggressive the shifts are, The idea in a shift kit is simple, You want to limit the slip during eh shift as much as reasonably possible but at same time not have it shifting like someone slammed into your rear.
Me I leave the 1-2 accum set up stock, wide band, corvette servo, .092 feed for second and 200 to 220 max PSI at WOT and it just works 3rd I like a bit larger at .100 to .110.
But the stock shafts and even drum will hold far more than most think if the build itself is right.
And of course never do anything dumb like lock converter in a shift no shaft or drum setup will handle that.

 

Oh I agree 100%, we've built a few upgraded units since I've worked here at this shop, a couple of which I built myself. I've never understood why people want to be rear-ended every shift, it just doesn't have to be that way.I try to tell people "Look at modern sports cars. They shift smooth and outpace anything you drive." I'd personally rather sacrifice a little HP for a more durable, smoother trans. My camaro will end up being my daily driver so yeah I'd like it smooth. I do appreciate everyone's input and wisdom, and hopefully this thread will alleviate some other people's concerns.

 

This is 100% Correct regarding 2wd Output-Shafts.
This is from testing that I did and passed onto Dana/ PBA many years ago at this point.



HD Input-Shafts have 1 ID Bands (slightly smaller Diameter area) going around the Shaft forward of the Sealing-Rings.
Shown below:


Early Shafts that are NON-HD with not have this ID Band.
Shown below:

Late Shafts that are NON-HD (that have Reluctor-Teeth) with have Two ID Bands or None.
Shown below with Two ID Bands:

 

Does anyone have info on what applications the 3 line output shafts were used in? And also the banded input shafts?

 

Since this thread is again active, I'm curious if the 4L80E also has hardened versus non-hardened input and output shafts; and if true how to ID them.