Twisted Axle Splines
10-19-2012, 06:04 AM
#1
Twisted Axle Splines D'oh!
Last time I went to the track was last December with Mike V, 94Z28Rag, CamaroRacing, hvyss, etc., where I set my new best time (video in sig). The last run of the day the rear decided to make some noise but I've only gotten around to checking it out NOW unfortunately (my work schedule has been absolutely horrid plus not having a place to work on the car sucks too). Upon pulling the axles this is what I found.
Those are Moser 31 spline axles, Ford 9", with a full spool. Tires are MT DR 295/15s.
I have not yet pulled the center section to inspect for any more damage but I strongly believe that my measly 455whp should not have been enough to twist the axle splines like that. However, Moser recommends that you have at least 1" of engagement on the axle splines which I have. I am wondering if I should lengthen the axle another 1/2" or so for more engagement being that I do drive the car on the street (which may have contributed to slowly weakening the axle). The other axle was undamaged.
What are your thoughts?
Last time I went to the track was last December with Mike V, 94Z28Rag, CamaroRacing, hvyss, etc., where I set my new best time (video in sig). The last run of the day the rear decided to make some noise but I've only gotten around to checking it out NOW unfortunately (my work schedule has been absolutely horrid plus not having a place to work on the car sucks too). Upon pulling the axles this is what I found.
Those are Moser 31 spline axles, Ford 9", with a full spool. Tires are MT DR 295/15s.
I have not yet pulled the center section to inspect for any more damage but I strongly believe that my measly 455whp should not have been enough to twist the axle splines like that. However, Moser recommends that you have at least 1" of engagement on the axle splines which I have. I am wondering if I should lengthen the axle another 1/2" or so for more engagement being that I do drive the car on the street (which may have contributed to slowly weakening the axle). The other axle was undamaged.
What are your thoughts?
Last edited by RamAir95TA; 10-19-2012 at 08:51 AM.
10-19-2012, 08:57 AM
#6
Nice job on that one, Joe!
Not surprising that the pssgr side axle is undamaged, since, unless you have a lot of anitroll bias in the car, the driver side is always subjected to more axle torque.
More engagement won't help the issue you're seeing; that would only help if you were seeing damage on the engaged length of the spline.
Get it back together and join us on the 17th again
Not surprising that the pssgr side axle is undamaged, since, unless you have a lot of anitroll bias in the car, the driver side is always subjected to more axle torque.
More engagement won't help the issue you're seeing; that would only help if you were seeing damage on the engaged length of the spline.
Get it back together and join us on the 17th again
10-19-2012, 09:00 AM
#7
Nice job on that one, Joe!
Not surprising that the pssgr side axle is undamaged, since, unless you have a lot of anitroll bias in the car, the driver side is always subjected to more axle torque.
More engagement won't help the issue you're seeing; that would only help if you were seeing damage on the engaged length of the spline.
Get it back together and join us on the 17th again
Not surprising that the pssgr side axle is undamaged, since, unless you have a lot of anitroll bias in the car, the driver side is always subjected to more axle torque.
More engagement won't help the issue you're seeing; that would only help if you were seeing damage on the engaged length of the spline.
Get it back together and join us on the 17th again
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10-19-2012, 09:24 AM
#8
Wernt people having alot of problems with twisting Moser axles? I believe the general consensus was switching to Strange. When was this rear assembled/when were these axles built? Maybe it was a bad batch? It looks like you didnt roll the splines, you legitimately TWISTED the axle like 15 degrees for the whole area that the axle has a smaller diameter where the splines are. More spline engagement wouldnt fix that. All wheel drive would though...
10-19-2012, 09:31 AM
#10
From what some of these guys are saying increasing the splines wouldn't help which makes sense. If the splines failed that'd be one thing but the entire axle is twisted.
The rear was built in 2004 from Moser.
I'll give the Strange axles a try next time.
The rear was built in 2004 from Moser.
I'll give the Strange axles a try next time.
10-19-2012, 09:36 AM
#12
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Guess I better check my Moser 9in axles before this weekend's race.
Are you going to call Moser? I'm curious what they think caused it. [EDIT just saw you posted] Moser has a axle load calculator that allows you to make sure you had enough splines to take 100% of the torque to one axle without issue.
Example: 550ft/lbs x 3.06 [4L60e first gear] x 4.11 [rear gear] x .90 [efficiency] = 6225 ft/lbs.
Moser lists the spline counts and ratings of it's 'Custom Alloy Axles'. [Ratings per axle]
30 spline - 6,200 ft/lbs
31 spline - 7,000 ft/lbs
33 spline - 8,200 ft/lbs
35 spline - 9,600 ft/lbs
40 spline - 12,000 ft/lbs
In theory 6225 is the TQ the axles share as you launch, so in my eyes a 31 spline axle should have held just fine. Even if you caught 100% of your torque on one axle.
[EDIT] Did you offer you anything, like a percentage off new axles or..? I mean their axle failed to spite it's 'approved' load rating.
-Dustin-
Are you going to call Moser? I'm curious what they think caused it. [EDIT just saw you posted] Moser has a axle load calculator that allows you to make sure you had enough splines to take 100% of the torque to one axle without issue.
Example: 550ft/lbs x 3.06 [4L60e first gear] x 4.11 [rear gear] x .90 [efficiency] = 6225 ft/lbs.
Moser lists the spline counts and ratings of it's 'Custom Alloy Axles'. [Ratings per axle]
30 spline - 6,200 ft/lbs
31 spline - 7,000 ft/lbs
33 spline - 8,200 ft/lbs
35 spline - 9,600 ft/lbs
40 spline - 12,000 ft/lbs
In theory 6225 is the TQ the axles share as you launch, so in my eyes a 31 spline axle should have held just fine. Even if you caught 100% of your torque on one axle.
[EDIT] Did you offer you anything, like a percentage off new axles or..? I mean their axle failed to spite it's 'approved' load rating.
-Dustin-
10-19-2012, 09:44 AM
#14
Tq breaks stuff!!!!!! I like it however not at your expense.... This kind of thing happens to axles over time with hard launching. I know Moser did have a few problems back when you stated that rear was new so quite possibly you have a set of the "in question" axles even though I feel both axles should have close to the same look ESPECIALLY with a spool.
Hey Joe,
Just for kicks why don't you PM Taner, he has a 9" in his 6spd car and he has yet to share any problems with it and he is nailing 1.2-1.3 60' times.........you know he is down to help
Hey Joe,
Just for kicks why don't you PM Taner, he has a 9" in his 6spd car and he has yet to share any problems with it and he is nailing 1.2-1.3 60' times.........you know he is down to help
10-19-2012, 09:53 AM
#16
Ugh, **** Moser. Since I bought the rear new, uninstalled, but off of a buddy they won't do anything for me. Which is fine because I'll just go with Strange axles instead. I'll be pulling the center section tonight and hopefully not find any more damage.
10-19-2012, 11:16 AM
#20
My 12 Bolt 33 spline Moser axles circa 2001 were chipped where the spool edge was but had no twisting after 10 years and hunderds of passes. Car was making 680RWHP when I sold the rear end and went 9in
I did go with 35 spline Strange Pro axles in the new setup because I got a screaming deal on it
I did go with 35 spline Strange Pro axles in the new setup because I got a screaming deal on it