Broken inner axel
10-03-2015, 07:12 PM
#1
Burning Brakes
Thread Starter
Broken inner axel
Hey fellas need some opinions an info. I went to the track 2 weeks ago and made one pass..... Second pass and bang as soon as I let the clutch out. Started looking today and I snapped the inner driver side axel.
Just for info a few years ago the same exact thing happened but at that time I broke an outer axel. Since then I have broke several outer axles and drive flags. Since then I have replaced the out axles with units from Duntov, I have replaced the drive flanges with units from Tom's last year I had the trans rebuilt (4 speed) last month I put in a set of half shafts from Ft Wayne..... Very nice pieces and I also put on a set of half shaft safety loops.
Anyway I was wanting to hold off on going with a full build on the rear because I have another car I am building. So my question is what is the best and strongest stock replacement unit I can buy?
The Tom's page is a bit confusing withe their description and I see VanSteel offers HD 17 spline units but they give zero description of them. Are they a stock replacement Unit?
What are my best options and what are you guys using?
Just for info a few years ago the same exact thing happened but at that time I broke an outer axel. Since then I have broke several outer axles and drive flags. Since then I have replaced the out axles with units from Duntov, I have replaced the drive flanges with units from Tom's last year I had the trans rebuilt (4 speed) last month I put in a set of half shafts from Ft Wayne..... Very nice pieces and I also put on a set of half shaft safety loops.
Anyway I was wanting to hold off on going with a full build on the rear because I have another car I am building. So my question is what is the best and strongest stock replacement unit I can buy?
The Tom's page is a bit confusing withe their description and I see VanSteel offers HD 17 spline units but they give zero description of them. Are they a stock replacement Unit?
What are my best options and what are you guys using?
10-04-2015, 12:18 AM
#3
Burning Brakes
Thread Starter
Didn't break the Duntov outer... The inner broke which was a stock unit.
10-04-2015, 07:32 AM
#4
Race Director
You'll break the outer next. I had one of those "Duntovs" (Zora is spinning in his grave). It twisted on regular street tires. No way it will survive in a car with any sort of real traction.
10-04-2015, 09:07 AM
#5
Hey fellas need some opinions an info. I went to the track 2 weeks ago and made one pass..... Second pass and bang as soon as I let the clutch out. Started looking today and I snapped the inner driver side axel.
Just for info a few years ago the same exact thing happened but at that time I broke an outer axel. Since then I have broke several outer axles and drive flags. Since then I have replaced the out axles with units from Duntov, I have replaced the drive flanges with units from Tom's last year I had the trans rebuilt (4 speed) last month I put in a set of half shafts from Ft Wayne..... Very nice pieces and I also put on a set of half shaft safety loops.
Anyway I was wanting to hold off on going with a full build on the rear because I have another car I am building. So my question is what is the best and strongest stock replacement unit I can buy?
The Tom's page is a bit confusing withe their description and I see VanSteel offers HD 17 spline units but they give zero description of them. Are they a stock replacement Unit?
What are my best options and what are you guys using?
Just for info a few years ago the same exact thing happened but at that time I broke an outer axel. Since then I have broke several outer axles and drive flags. Since then I have replaced the out axles with units from Duntov, I have replaced the drive flanges with units from Tom's last year I had the trans rebuilt (4 speed) last month I put in a set of half shafts from Ft Wayne..... Very nice pieces and I also put on a set of half shaft safety loops.
Anyway I was wanting to hold off on going with a full build on the rear because I have another car I am building. So my question is what is the best and strongest stock replacement unit I can buy?
The Tom's page is a bit confusing withe their description and I see VanSteel offers HD 17 spline units but they give zero description of them. Are they a stock replacement Unit?
What are my best options and what are you guys using?
https://www.corvetteforum.com/forums...ide-yokes.html
Are their any markings on your yokes ?
The one that broke does it have a GM stamp or is it blank ?
Mine that broke has no markings anywhere.
10-04-2015, 11:24 AM
#6
Burning Brakes
Thread Starter
Does it look like this ? https://www.corvetteforum.com/forums...ide-yokes.html Are their any markings on your yokes ? The one that broke does it have a GM stamp or is it blank ? Mine that broke has no markings anywhere.
So now I have to ask myself do I just replace the inner axels or do I go to a full on build its 30 spline units. I'm not really ready for a full build and was curios to see what option are out there for stock 17 spline units.
I will have to inspect it closer to see if there is damage to the yoke and also if there is GM stamped on it. I can tell you these have been in the car and untouched for 30 years so it's unlikely they are anything other than GM. I will be pulling the rear out today and open it up to see if there is any other damage inside.
I hate to keep breaking stuff and didn't think I would have to go to the big 30 spline units..... My engine does not make any insane power but I have big sticky tires and a 4 speed which is killing it. I have had thoughts of gouging a Turbo 400..... As much as I like a manual an auto would be cheaper than beefing up the rear.
10-04-2015, 10:23 PM
#7
Drifting
I know the only quality stock 17 spline outers are Toms or Spencer Forge.
I'm not sure if both also offer inner in stock replacement, but that's where I would look.
...also weigh the cost of the stock replacement and the upgraded rear. If you are at the power level to be breaking things, it may be worth it in the long run to bite the bullet now and do it right rather then paying less multiple times. (I had the same dilemma when doing my trailing arms and went with Tom's 31 spline outers. As soon as the rear end breaks, it will get the 30 spline build)
I'm not sure if both also offer inner in stock replacement, but that's where I would look.
...also weigh the cost of the stock replacement and the upgraded rear. If you are at the power level to be breaking things, it may be worth it in the long run to bite the bullet now and do it right rather then paying less multiple times. (I had the same dilemma when doing my trailing arms and went with Tom's 31 spline outers. As soon as the rear end breaks, it will get the 30 spline build)
10-05-2015, 11:29 AM
#8
Burning Brakes
Thread Starter
I know the only quality stock 17 spline outers are Toms or Spencer Forge.
I'm not sure if both also offer inner in stock replacement, but that's where I would look.
...also weigh the cost of the stock replacement and the upgraded rear. If you are at the power level to be breaking things, it may be worth it in the long run to bite the bullet now and do it right rather then paying less multiple times. (I had the same dilemma when doing my trailing arms and went with Tom's 31 spline outers. As soon as the rear end breaks, it will get the 30 spline build)
I'm not sure if both also offer inner in stock replacement, but that's where I would look.
...also weigh the cost of the stock replacement and the upgraded rear. If you are at the power level to be breaking things, it may be worth it in the long run to bite the bullet now and do it right rather then paying less multiple times. (I had the same dilemma when doing my trailing arms and went with Tom's 31 spline outers. As soon as the rear end breaks, it will get the 30 spline build)
10-06-2015, 01:55 PM
#10
Pro
I just bit the bullet and bought all Tom's stuff. The 12 bolt diff, 1480 kit and the big half shafts, 30 spline inners and outers. I don't like breaking stuff, it can get dangerous. I do have a set of 30 spline outer axles I'll sell. They are new but they have bigger studs, 3" by 1//2"
10-06-2015, 05:58 PM
#11
Melting Slicks
I phoned Tom from Toms differential, and asked him about his stock (17) spline replacements. He pretty much told me not to go that route and suggested to put in the 30 spline units he has. I really didn't want to stray from the 17 spline units, so I kept looking. I have also heard of others having troubles with Toms 17 spline units so I wondered if this is why he tried to steer me away from those.
I ended up getting these from MidAmerica.....they seem like good pieces, advertised good for 500 HP, and have to be better than any of the $100-$125 offshore junk....
http://www.mamotorworks.com/Corvette...-each-602950-1
I ended up getting these from MidAmerica.....they seem like good pieces, advertised good for 500 HP, and have to be better than any of the $100-$125 offshore junk....
http://www.mamotorworks.com/Corvette...-each-602950-1
10-07-2015, 12:23 PM
#12
Drifting
Here's the problem with 17 spline stub axles. They're too small. This is why Tom doesn't recommend them. They will always break in the splines. The stock originals (pre 1974) will handle 500 hp no problem. They will not handle the shock load from a hard launch.
Here's the story of two cars. Both are 71's with stock stub axles. 71A has a 496 BB auto 650hp/700tq. 71B has a 355 4spd 350hp/400tq. 71A launches hard and gets a little air under the front tires. Did not twist the stub axles. 71b launches hard and does twist the stub axles.
Here's a 3rd car, 76. BB auto. over 300 passes on stock replacement stub axles. One bad launch twisted everything including the stub axles but they didn't break. The ring gear shattered because of bearing cap stretch. All 3 now run 30 spline stub axles.
All the (HD) stub axles I see on the market have a modified end for u-joint retention. Where they never break at. They advertise twice the Rockwell hardness (or more) of a stock OE stub axle. But they don't give the actual number. Stock midyear HD stub axles Rockwell in the mid 20's. Twice that puts them near 50. Very hard but brittle. They will handle the torque but not the shock load. Late 70's Rockwell in the single digits. Even at twice the hardness they don't come close to an OEM midyear axle.
Inferior stub axles that have flooded the market: Cagotzmann has witnessed them first hand. These have the torque resistance of a tootsie roll. And that's what they look like when they break. There is only one way to identify them and I wouldn't be surprised if that gets changed soon.
80-82 Dana 44 OEM stub axles. These are so soft you can whittle on them with a sharp knife. But they don't twist, even in 10 second cars. Because they are 30 spline.
Only one company makes a decent 17 spline replacement stub axle at a decent price. It rockwells right at 30. Stronger than any OEM but soft enough not to snap off. But it has its limits because of the 17 splines. There just isn't a 17 spline axle that's going to hold up to clutch dumps on slicks. Not even Toms.
Mike
Here's the story of two cars. Both are 71's with stock stub axles. 71A has a 496 BB auto 650hp/700tq. 71B has a 355 4spd 350hp/400tq. 71A launches hard and gets a little air under the front tires. Did not twist the stub axles. 71b launches hard and does twist the stub axles.
Here's a 3rd car, 76. BB auto. over 300 passes on stock replacement stub axles. One bad launch twisted everything including the stub axles but they didn't break. The ring gear shattered because of bearing cap stretch. All 3 now run 30 spline stub axles.
All the (HD) stub axles I see on the market have a modified end for u-joint retention. Where they never break at. They advertise twice the Rockwell hardness (or more) of a stock OE stub axle. But they don't give the actual number. Stock midyear HD stub axles Rockwell in the mid 20's. Twice that puts them near 50. Very hard but brittle. They will handle the torque but not the shock load. Late 70's Rockwell in the single digits. Even at twice the hardness they don't come close to an OEM midyear axle.
Inferior stub axles that have flooded the market: Cagotzmann has witnessed them first hand. These have the torque resistance of a tootsie roll. And that's what they look like when they break. There is only one way to identify them and I wouldn't be surprised if that gets changed soon.
80-82 Dana 44 OEM stub axles. These are so soft you can whittle on them with a sharp knife. But they don't twist, even in 10 second cars. Because they are 30 spline.
Only one company makes a decent 17 spline replacement stub axle at a decent price. It rockwells right at 30. Stronger than any OEM but soft enough not to snap off. But it has its limits because of the 17 splines. There just isn't a 17 spline axle that's going to hold up to clutch dumps on slicks. Not even Toms.
Mike
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sfsvettes (10-10-2015)
10-07-2015, 04:45 PM
#13
Burning Brakes
Thread Starter
I got the rear pulled out and the other axel removed, it wasn't broken but the splines were hammered and starting to twist. Neither axle is stamped GM anywhere on it as a matter of fact there are zero marking or stamps anywhere.....
Do all GM axles have a stamp?
As I said Have had this car for over 30 years and the inner axles have never been touched so if the inners were replaced they were done so prior to 1980. I dont know if the cheap stuff was floating around back then...doubt it.
Anyway I ordered a set of 17 splines from Tom just to get the car rolling for now...its a band aid! I will baby the car for now. I have to work out a lean condition in the engine. When I was at the track 1 was able to make 1 pass and the car was 11mph slower than usual...I pulled plugs and they were so lean they were almost green! made some adjustment and went for a second pass....never made it off the line.
Anyway I figure I will get the 17 splines in there and fix the lean condition and then start making moves to go 30 spline inners with a full build and change the outers. It seems that nothing other than that will hold up.
Do all GM axles have a stamp?
As I said Have had this car for over 30 years and the inner axles have never been touched so if the inners were replaced they were done so prior to 1980. I dont know if the cheap stuff was floating around back then...doubt it.
Anyway I ordered a set of 17 splines from Tom just to get the car rolling for now...its a band aid! I will baby the car for now. I have to work out a lean condition in the engine. When I was at the track 1 was able to make 1 pass and the car was 11mph slower than usual...I pulled plugs and they were so lean they were almost green! made some adjustment and went for a second pass....never made it off the line.
Anyway I figure I will get the 17 splines in there and fix the lean condition and then start making moves to go 30 spline inners with a full build and change the outers. It seems that nothing other than that will hold up.
10-07-2015, 04:45 PM
#14
Burning Brakes
Thread Starter
I just bit the bullet and bought all Tom's stuff. The 12 bolt diff, 1480 kit and the big half shafts, 30 spline inners and outers. I don't like breaking stuff, it can get dangerous. I do have a set of 30 spline outer axles I'll sell. They are new but they have bigger studs, 3" by 1//2"
PM sent
10-10-2015, 02:47 PM
#15
BubbaHut
rear diff
I just bit the bullet and bought all Tom's stuff. The 12 bolt diff, 1480 kit and the big half shafts, 30 spline inners and outers. I don't like breaking stuff, it can get dangerous. I do have a set of 30 spline outer axles I'll sell. They are new but they have bigger studs, 3" by 1//2"
4.11 with big shafts
I need some of this good stuff for my 72. Just blew up my 4.11 a couple weeks ago.
10-10-2015, 02:53 PM
#16
BubbaHut
10-12-2015, 09:24 AM
#17
Burning Brakes
Thread Starter
10-12-2015, 03:02 PM
#18
Team Owner
I bought these custom hardened ones 25 years ago and they are still going strong.
http://www.mamotorworks.com/Corvette...-each-602950-1
http://www.mamotorworks.com/Corvette...-each-602950-1
