twisted splines.

[undy]

I'm starting a ring and pinion replacement on my Ford 9" diff. I'm going from a 3.70 to a more street friendly 3.25 ration. In pulling my axles to drop the pumpkin I found the driver's side axle shaft's splines had begun to twist. I can't imagine why that happened I'm running a Currie 28 spline crate rear end with a TSD posi-carrier.

My options as I see it are:

1. Let her ride and hope for the best (no more twist and ultimate axle failure)

2. See if Currie has a stronger set of 28 spline axles and replace them. I don't
think they do though.

3. Replace axles and posi unit with a 31 spline setup.

4. Replace axles and posi unit with a 35 spline setup.

What does everyone think?



Dave

[CHANMADD]

serious launches and burn outs are going to do that to almost any axle you buy. Driven like at the drags,replacing axles will be a regular thing.
John

[undy]

Originally Posted by CHANMADD

serious launches and burn outs are going to do that to almost any axle you buy. Driven like at the drags,replacing axles will be a regular thing.
John

100% street.. never raced. I do run drag radials though.

[blykins]

Dave, might as well make it right before you button it back up. Axles are cheap.....you can get a set of Strange axles in 28 or 31 spline for around $200. If it were mine, I'd go with at least 31 spline.

[Silverback51]

Years ago I had an "A" Class Econorail with a big block Chevy.

We would blue the axles to track how much they twisted. We always used about 45 degrees as an idicator it was time to replace them with a new set.

[undy]

It takes about 10 minutes to pull an axle. I might let it go for now and pull it at the end of next season to see if I've more twist. That is, unless.. I twist one in two first. It'll cost me around a grand to upgrade to 31 spline and right at $1500 to go with 35 spline. The difference being that there's a limited selection of posi units with 35 splines. If I replace things I'm inclined to go to the 35 splines.. Decisions, decisions...

[Power Surge]

I'd contact a real race axle company (Moser, Strange, etc) and just have them make you a set in the same configuration.

[undy]

Originally Posted by Power Surge

I'd contact a real race axle company (Moser, Strange, etc) and just have them make you a set in the same configuration.

...and stay with the 28s? I thought Currie's axles were of similar quality?

[Rick Parker]

This is your problem: "KC Pond 482 S/O" (If that is a problem?) Exerting Massive Torque leaning on 28 spline axles with sticky tires.




Do NOT leave it as it. You can change a very few pieces in your existing posi set up and do yourself good by changing to 31 spline axles. If that axle twists the end off as it is close to doing, your car will make an immediate dangerous turn to the side of the broken axle, very unsafe and uncontrolable. Buy new axles made to the necessary length, resist the temptation to respline existing axles after shotening them. After shortening (mostly on 28 spline applications) the material is not hardened as the original splined area and is weaker than before.

When I redid mine a few years ago, even though the little 289 has nowhere near the torque you have, I upgraded to a 31 spline 9" Nodular carrier with new "Good" axles. By doing this I know I will not ever have to contend with an axle or differential failure.

From Strange's Website"

We manufacture Ford 9” 28-spline axles for low
horsepower and lightweight “street-rod”
applications. Although our 28-spline S/S axle
is stronger than OEM 28-spline shafts-
28-spline S/S axle shafts are
significantly (38%) torsionally weaker in
comparison to 31-spline S/S axles. We
strongly recommend to upgrade to 31-spline
axle shafts for street applications.

Take it for what it's worth..........


Here are some very good sources:




http://www.dutchmanms.com/
http://www.moserengineering.com/
http://www.strangeengineering.net/catalog/index.html

[Ronbo]

Although there's some spline erosion, the axle itself is twisting. Spline count is not the problem it's the axle material itself.

Retire it to garage wall art and get a new one...

Think of the stories: "Look what I did to these!"

[eschaider]

Originally Posted by blykins

Dave, might as well make it right before you button it back up. Axles are cheap.....you can get a set of Strange axles in 28 or 31 spline for around $200. If it were mine, I'd go with at least 31 spline.

+1 Dave,

When you do it go to 31 splines. There is a world of difference in terms of strength. When you go to 31 splines you will also have to replace the side gears in the differential. Not a big deal from a cost standpoint but a little work from your standpoint. Great experience though and good step towards a significant step up in reliability.

Thirty five spline axles are extraordinarily strong and come very close to a set it and forget it part. When you use a pair of these axles you ought to have a minimum 3.25" bearing bore in your 9" carrier. If you are using a Dana 44 then I would probably stop at 31 splines. I am unaware of anyone making '44s with 3.25" bearing bores and the wall thickness on the differential housing at the bearing gets very thin. The thin wall becomes your first point of failure, so ... you get the picture.

Whatever you do don't go back to 28 splines even in a quality axle like Strange. The 28 spline axle is for a lower power/performance level than you are capable of creating.

Ed

[Fordzilla]

Do not let it go, pull them & replace them. Go with 31 spline Moser axles. They will be the last set you will ever purchase for the car. 35 spline is way overkill & as stated previously, limits your posi set up options. I am running Moser 31 spline axles & Moser center section Detroit locker 3.70 gear in a massively reinforced 9" Ford housing. Putting the torque & horse of a blown 542 FE through it to Drag Radials. Not in the least bit concerned about hurting 31 spline Mosers. They'll take it.
Regards,

[undy]

Thanks guys.. I'll take everyone's advice and go with the 31 spline setup, using Moser, Strange or Dutchman axles. I'll nail this down tomorrow after making some phone calls.

Next decision.. Which Carrier to use? True-Trac, gears only no clutches .. or .. standard Ford/TSD type clutch lim-slip .. or .. Detroit locker. I can get a "low mile" NASCAR small bearing 31 spline Detroit Locker for quite a bit less that $300, or a new one for $475. What's everyone's preferences and rational behind it??

You guys are da bomb

Dave

BTW.. Thanks for the PM Rick P.

[Lawler]

Undy,

I'm gonna watch your rebuild closely. I have always been concerned about twisting an axle while under power and having to deal with the sudden change in direction. I have looked at the 31 spline mosers as well and am still in process trying to decide if I should change switch from the 3.70.

Kinton

[Bernica]

We used to paint a very straight stipe down the axle, then pull them after racing to see if there was any "licorice twist" to the stripe. A quick way to know if you have twisted. Old school, I know, but it helps.

[Silverback51]

Originally Posted by Bernica

We used to paint a very straight stipe down the axle, then pull them after racing to see if there was any "licorice twist" to the stripe. A quick way to know if you have twisted. Old school, I know, but it helps.

Same as we did with the blueing and a light scribe mark.

All axles will twist to a certain degree when used in high performance vehicles.

[Rick Parker]

If you snap an axle under hard acceleration you'll head in a direction you don't want to, and have no control over it. It could, ...no, it WILL get ugly, REAL FAST.

[Bernica]

Everyone's worst nightmare. It's worth doing it right and keeping it that way....

[xracerbob]

As far as the diff goes, Detroit lockers are not very friendly for street use. For traction, they are excellent and very durable, however they can be noisy and especially the occasional BANG you get when backing out of a parking spot and turning. You will swear someone just hit you.

I have used Torsen differentials in the past and they are great. No clutches, smooth engagement, very durable. They are expensive- the last one I bought was about $480. I wish they made one for the Jag (Dana) rear. Also, no friction modifier is necessary with Torsen diffs.

http://www.torsen.com/

[B.M.B.C]

bob. try this for jaguar lsd, expensive but the best. http://www.quaife.co.uk/What-is-a-Qu...B-differential
http://www.quaife.co.uk/shop_categor...tegory_id/1274

sorry for thread drift

thanks