Axle Twist - Opinions on these please.

[LemonWedge]

My car is a street strip deal that typically runs around 11.70's / 1.61 60's. It weighs about 3700 with me in it. I was taking apart the 8-3/4" rear end in prep. to narrow it by an inch to optimize tire clearance, and swap out the Detroit locker for a spool. This is what I found:

These axles are only 3 years old, with only 41 passes on them. They are aftermarket hardened units from Dr. Diff. Are they done? My plan to narrow would allow me to capture 1/2" more spline on each one, but I don't even know if they would slide into a spool like this? I'll call Dr. Diff tomorrow, but what do you guys make of this?

 

[Phil McGrath]

They look done too me... If you had the added 1/2 before, they might have lived a longer life.

 

[383man]

Wow. Whats weird is I still have stock axle's in my 63 and with the old 440 that ran a best of 11.49 I had about 30 passes on it and with the 493 thats hit 10.70's I have about 16 passes on it. It is a street car that I drive alot on the street but the last time I had my axles out which was a couple years ago my splines were still straight as an arrow. I have put about 12 passes on it since I had the axle's out.
But with any twisting on them I would hesitate to use them again. Ron

 

[LemonWedge]

The car had been 11.90's on stock axles when it broke the sure-grip unit. At that time, the stock axles were fine (and I still have them) but I "upgraded" to these. I'm anxious to see what Cass has to say. If he just says "oh well", I may just go back to the stock axles. I'm hopeful that he may find it strange that his axles didn't stand up to my power level, and be willing to replace them (??).

 

[JRL]

they will not fit if you shorten them. I had similar looking 35 spline axles on a ford 9". Never replaced them.
Maybe I was just lucky

 

[dvw]

Call Cass himself and ask. He won't steer you wrong. (406) 883-4772
Doug

 

[383man]

The car had been 11.90's on stock axles when it broke the sure-grip unit. At that time, the stock axles were fine (and I still have them) but I "upgraded" to these. I'm anxious to see what Cass has to say. If he just says "oh well", I may just go back to the stock axles. I'm hopeful that he may find it strange that his axles didn't stand up to my power level, and be willing to replace them (??).

I am curious what he says or if he sells a stronger axle as I plan to put stronger axles in mine. Ron

 

[66Satellite47]

Gee, when I bought my '65 Coronet 426 Wedge 4 speed 8 3/4 car, the stock right axle had about 1/16th turn in the splines, although the twist was in one spot. I replaced it. Later I went to a narrowed Dana 60 with Strange axles. About 2000 runs on the Dana at 11.00's down to 10.50's. I did paint a white stripe on the Strange axle when new. No change. Just say'n.

 

[Cranky]

The car had been 11.90's on stock axles when it broke the sure-grip unit. At that time, the stock axles were fine (and I still have them) but I "upgraded" to these. I'm anxious to see what Cass has to say. If he just says "oh well", I may just go back to the stock axles. I'm hopeful that he may find it strange that his axles didn't stand up to my power level, and be willing to replace them (??).

Don't use those anymore because they will continue to twist until one breaks. Also, what broke in the Sure Grip that you were using?

Gee, when I bought my '65 Coronet 426 Wedge 4 speed 8 3/4 car, the stock right axle had about 1/16th turn in the splines, although the twist was in one spot. I replaced it. Later I went to a narrowed Dana 60 with Strange axles. About 2000 runs on the Dana at 11.00's down to 10.50's. I did paint a white stripe on the Strange axle when new. No change. Just say'n.

We were going 10.70 with factory stock Dana 60 axles for a pretty good while with a 4 speed no less until a tech inspector finally noticed lol. It's surprising how strong they are....

 

[LemonWedge]

Don't use those anymore because they will continue to twist until one breaks. Also, what broke in the Sure Grip that you were using?
QUOTE]

It was a stock style clutch sure grip unit and it broke the side gears. I actually did that twice before I finally went to the Detroit Locker and these axles. At that time I also installed a Moser backbrace and MW steel maincaps. The only reason I was going to go to a spool is because I am, and plan to do more racing these days, and I have found that racing the stripe with a locker can be an adventure, to say the least. Its also time for me to get new tires, so I did some math and figured if I narrow the rear by an inch, I can go to 275/60 street tires, and 28x9 radial slicks.

 

[HEMI-ITIS]

When it broke,did the tach go to the moon?? If so,you may want to check the trans also!

 

[Cranky]

Don't use those anymore because they will continue to twist until one breaks. Also, what broke in the Sure Grip that you were using?
QUOTE]

It was a stock style clutch sure grip unit and it broke the side gears. I actually did that twice before I finally went to the Detroit Locker and these axles. At that time I also installed a Moser backbrace and MW steel maincaps. The only reason I was going to go to a spool is because I am, and plan to do more racing these days, and I have found that racing the stripe with a locker can be an adventure, to say the least. Its also time for me to get new tires, so I did some math and figured if I narrow the rear by an inch, I can go to 275/60 street tires, and 28x9 radial slicks.

A buddy is going low mid 11's with a loaded up 70 6 pack Challenger using a cone type Sure Grip. I set it up for him many years ago and then machined the cones about 5 years later and that was about 10 years ago. He's still on stock axles too. What kind of car are you running and do you have any Sure Grips laying around that you want to get rid of? I have a couple of rears that I robbed the SG's from to build for others.

 

[66Satellite47]

Don't use those anymore because they will continue to twist until one breaks. Also, what broke in the Sure Grip that you were using?

We were going 10.70 with factory stock Dana 60 axles for a pretty good while with a 4 speed no less until a tech inspector finally noticed lol. It's surprising how strong they are....

I agree that stock Dana 60 axles are stout. When I switched to a Dana 60 I narrowed it, so I went to aftermarket axles. Have you continued using stock axles? My point is if you go with a Dana 60, good aftermarket axles it's really tough. Other axle combinations, 9" Ford or a 8 3/4 when extensively modified seem to be durable. A Dana 60 with aftermarket axles seems to me to be very durable at a somewhat lower cost, even though heavier. Just my opinion.

 

[69 GTX]

Did you jig up the rear to check to see if it was still straight after welding on the brace? Housing might be tweaked a little causing your problem.

 

[LemonWedge]

Hemi-it is:
The powerlock break was years ago. Its had a locker in it for a few years now, and that has been just fine.

69GTX:
No, I didn't. The guy that braced it for me welded up a make-shift jig to hold it straight and was convinced it was straight. It goes together just fine, and as said, it didn't break anything, just twisted the axles, which I don't think would be related to warpage.

- - - Updated - - -

Just talked with Cass. He was quick to point out that nobody offers warranty's on 30-spline axles. He is not willing to replace them for free, but is willing to offer a discount on a set of 35-splines and a 35-spline spool, and offer a warranty on the new set. I suppose that is fair to both of us. Anybody interested in a Detroit Locker for an 8-3/4"??

 

[Mike Gaines]

Here is the answer to all 8 3/4 problems....I decided NOT to throw money at my 8 3/4 because no amount of money will make it strong enuf not to break, eventually...if you put a lot of runs on your car that runs low, low 11's or faster.

 

[splicer]

LemonWedge: You don't have a differential problem...you have a 'garbage axle' problem. Nothin wierd...just junk axles

I've been running an 8 3/4 with Strange 30 spline axles and a Detroit locker for 5 years now with NO issues....3750 LBS at 10.53 sec and 128 MPH

Get some Strange or Moser axles...30 spline is fine......keep the locker....and you'll be fine..

John B.

 

[Budnicks]

Just don't reuse those axles...

 

[dvw]

Axle twist can depend on how hard it leaves. My 11.0 car ran factory axles for years, never twisted. I raced my wife's 12.50 4 speed car only a year, twisted the shafts just like the ones pictured. If I was to upgrade to a spool I'd run 35 spline. Or better yet a Dana.
Doug

 

[LemonWedge]

I am curious what he says or if he sells a stronger axle as I plan to put stronger axles in mine. Ron

Ron, he does have 35 spline axles, that he warranty's for 10 years. The only 8-3/4 differential that offers 35 spline sleeves, however, is a spool. Of course he has reasonably priced spools too.