New RPM Differential Break In
03-20-2017, 08:31 AM
#1
Drifting
Thread Starter
New RPM Differential Break In
My '12 GS is finally back together after an A6 rear shaft failure took out the stock Z06 3.42 differential. The stock Z06 rear was replaced with a RPM Level 4 Z06 carrier with 2.93 gears. How many street miles are necessary for break-in before I go to the track?
Thanks in advance.
BIGMAC
'98 C5 (Avatar Pic)
'12 C6 GS (Broken)
Thanks in advance.
BIGMAC
'98 C5 (Avatar Pic)
'12 C6 GS (Broken)
03-21-2017, 01:13 PM
#4
Race Director
I was told with my rebuilt diff from DTE to vary the rpm's and no hard throttle for 500 miles.
Different gear use for different rpm's.
I also changed the oil.
Concerning track use, I have no idea but I would think another 500 to be safe, just what I would do.
Different gear use for different rpm's.
I also changed the oil.
Concerning track use, I have no idea but I would think another 500 to be safe, just what I would do.
03-22-2017, 11:15 AM
#5
Team Owner
My '12 GS is finally back together after an A6 rear shaft failure took out the stock Z06 3.42 differential. The stock Z06 rear was replaced with a RPM Level 4 Z06 carrier with 2.93 gears. How many street miles are necessary for break-in before I go to the track?
Thanks in advance.
BIGMAC
'98 C5 (Avatar Pic)
'12 C6 GS (Broken)
Thanks in advance.
BIGMAC
'98 C5 (Avatar Pic)
'12 C6 GS (Broken)
Did it break due to a big stall you were running? or tires hooking hard on the track? or combo of both?
Curious on the A6's shaft failure
Thanks,Matt
03-23-2017, 07:41 AM
#6
Drifting
Thread Starter
I wish I knew what cased the A6 shaft failure. It happened at launch on the 3rd shakedown run for a new build car. On runs #1 and #2 the NT05R 345/30/19 DR's spun badly so too much hook was not the issue. I suspected I would have traction issues (750 RWHP) but figured I would give it a go anyway. The trans guy felt the cause may have been wheel hop- I do not recall any but with all that was going on who knows. As to the stall..see below.
What I do know is when the trans came out of the car it had a PATC converter of unknown stall instead of the Pro Torque 2600 stall unit I paid the car builder for. When the trans was returned to the trans shop for repair he determined from the serial number it had been built some two years prior to when my build started. I can only assume my car builder installed a used a transmission out of another car instead of sending my stock unit to be built. The shop that built my car is now out of business and the co-owner has so far ignored my requests to speak to him for an explanation. I HOPE the trans had been trashed during its period prior to being in my car and that led to the shaft failure. The trans guy went through everything to make sure all was OK and I had an FTI converter installed.
I am led to believe A6 rear shaft failures are unusual and that is why there is no aftermarket upgraded version. I will hope for the best! I now have M&H 325/45/17 DR's mounted on Weld wheels that will hopefully provide adequate traction (provided they don't set off all hell with Active Handing / Traction Control due to the 28" diameter being out of the tolerance range for the "nannies").
Wish me luck!
BIGMAC
03-23-2017, 08:17 AM
#7
Team Owner
Matt,
I wish I knew what cased the A6 shaft failure. It happened at launch on the 3rd shakedown run for a new build car. On runs #1 and #2 the NT05R 345/30/19 DR's spun badly so too much hook was not the issue. I suspected I would have traction issues (750 RWHP) but figured I would give it a go anyway. The trans guy felt the cause may have been wheel hop- I do not recall any but with all that was going on who knows. As to the stall..see below.
What I do know is when the trans came out of the car it had a PATC converter of unknown stall instead of the Pro Torque 2600 stall unit I paid the car builder for. When the trans was returned to the trans shop for repair he determined from the serial number it had been built some two years prior to when my build started. I can only assume my car builder installed a used a transmission out of another car instead of sending my stock unit to be built. The shop that built my car is now out of business and the co-owner has so far ignored my requests to speak to him for an explanation. I HOPE the trans had been trashed during its period prior to being in my car and that led to the shaft failure. The trans guy went through everything to make sure all was OK and I had an FTI converter installed.
I am led to believe A6 rear shaft failures are unusual and that is why there is no aftermarket upgraded version. I will hope for the best! I now have M&H 325/45/17 DR's mounted on Weld wheels that will hopefully provide adequate traction (provided they don't set off all hell with Active Handing / Traction Control due to the 28" diameter being out of the tolerance range for the "nannies").
Wish me luck!
BIGMAC
I wish I knew what cased the A6 shaft failure. It happened at launch on the 3rd shakedown run for a new build car. On runs #1 and #2 the NT05R 345/30/19 DR's spun badly so too much hook was not the issue. I suspected I would have traction issues (750 RWHP) but figured I would give it a go anyway. The trans guy felt the cause may have been wheel hop- I do not recall any but with all that was going on who knows. As to the stall..see below.
What I do know is when the trans came out of the car it had a PATC converter of unknown stall instead of the Pro Torque 2600 stall unit I paid the car builder for. When the trans was returned to the trans shop for repair he determined from the serial number it had been built some two years prior to when my build started. I can only assume my car builder installed a used a transmission out of another car instead of sending my stock unit to be built. The shop that built my car is now out of business and the co-owner has so far ignored my requests to speak to him for an explanation. I HOPE the trans had been trashed during its period prior to being in my car and that led to the shaft failure. The trans guy went through everything to make sure all was OK and I had an FTI converter installed.
I am led to believe A6 rear shaft failures are unusual and that is why there is no aftermarket upgraded version. I will hope for the best! I now have M&H 325/45/17 DR's mounted on Weld wheels that will hopefully provide adequate traction (provided they don't set off all hell with Active Handing / Traction Control due to the 28" diameter being out of the tolerance range for the "nannies").
Wish me luck!
BIGMAC
Thank you for getting back with the info - man sorry to hear that that happened, shops do that kinda of stuff all too often and it's not fair to us as consumers.
I will be eagerly awaiting your results and I do hope that the M&H 325's do you well!
Thanks,Matt
03-23-2017, 08:35 AM
#8
Matt,
I wish I knew what cased the A6 shaft failure. It happened at launch on the 3rd shakedown run for a new build car. On runs #1 and #2 the NT05R 345/30/19 DR's spun badly so too much hook was not the issue. I suspected I would have traction issues (750 RWHP) but figured I would give it a go anyway. The trans guy felt the cause may have been wheel hop- I do not recall any but with all that was going on who knows. As to the stall..see below.
What I do know is when the trans came out of the car it had a PATC converter of unknown stall instead of the Pro Torque 2600 stall unit I paid the car builder for. When the trans was returned to the trans shop for repair he determined from the serial number it had been built some two years prior to when my build started. I can only assume my car builder installed a used a transmission out of another car instead of sending my stock unit to be built. The shop that built my car is now out of business and the co-owner has so far ignored my requests to speak to him for an explanation. I HOPE the trans had been trashed during its period prior to being in my car and that led to the shaft failure. The trans guy went through everything to make sure all was OK and I had an FTI converter installed.
I am led to believe A6 rear shaft failures are unusual and that is why there is no aftermarket upgraded version. I will hope for the best! I now have M&H 325/45/17 DR's mounted on Weld wheels that will hopefully provide adequate traction (provided they don't set off all hell with Active Handing / Traction Control due to the 28" diameter being out of the tolerance range for the "nannies").
Wish me luck!
BIGMAC
I wish I knew what cased the A6 shaft failure. It happened at launch on the 3rd shakedown run for a new build car. On runs #1 and #2 the NT05R 345/30/19 DR's spun badly so too much hook was not the issue. I suspected I would have traction issues (750 RWHP) but figured I would give it a go anyway. The trans guy felt the cause may have been wheel hop- I do not recall any but with all that was going on who knows. As to the stall..see below.
What I do know is when the trans came out of the car it had a PATC converter of unknown stall instead of the Pro Torque 2600 stall unit I paid the car builder for. When the trans was returned to the trans shop for repair he determined from the serial number it had been built some two years prior to when my build started. I can only assume my car builder installed a used a transmission out of another car instead of sending my stock unit to be built. The shop that built my car is now out of business and the co-owner has so far ignored my requests to speak to him for an explanation. I HOPE the trans had been trashed during its period prior to being in my car and that led to the shaft failure. The trans guy went through everything to make sure all was OK and I had an FTI converter installed.
I am led to believe A6 rear shaft failures are unusual and that is why there is no aftermarket upgraded version. I will hope for the best! I now have M&H 325/45/17 DR's mounted on Weld wheels that will hopefully provide adequate traction (provided they don't set off all hell with Active Handing / Traction Control due to the 28" diameter being out of the tolerance range for the "nannies").
Wish me luck!
BIGMAC
If that was the case, then I believe what most likely happened was flex between the transmission case and the diff, which broke the ears and that would then obviously cause the output shaft to snap. Another member on here experienced the same thing lately. So, I don't think that the problem is weakness of the output shaft.
I think that the only way to avoid that repeating itself is to install a brace, and I was waiting for ECS to restart production on those, but when I contacted them lately, Chris told me that they had put production of those on hold, because they're extremely busy, it seems. They must be, because I've been trying since the 4 march to get a fuel system and a tensioner ordered, and I still haven't gotten a shipping quote as yet.
The other thing I would do would be to install some Hinson mounts. I have a set of of those, but I haven't gotten around to installing them as yet, because one side looks like it might be a bitch to get at.
Anything that you can do to reduce flex and eliminate wheel hop will be a big help IMV.
Good luck with it regardless.
Last edited by CI GS; 03-23-2017 at 08:35 AM.
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C5-Fan (03-27-2018)
03-23-2017, 09:13 AM
#9
Drifting
Thread Starter
If I recall correctly, the the ears broke off your diff housing, correct?
If that was the case, then I believe what most likely happened was flex between the transmission case and the diff, which broke the ears and that would then obviously cause the output shaft to snap. Another member on here experienced the same thing lately. So, I don't think that the problem is weakness of the output shaft.
I think that the only way to avoid that repeating itself is to install a brace, and I was waiting for ECS to restart production on those, but when I contacted them lately, Chris told me that they had put production of those on hold, because they're extremely busy, it seems. They must be, because I've been trying since the 4 march to get a fuel system and a tensioner ordered, and I still haven't gotten a shipping quote as yet.
The other thing I would do would be to install some Hinson mounts. I have a set of of those, but I haven't gotten around to installing them as yet, because one side looks like it might be a bitch to get at.
Anything that you can do to reduce flex and eliminate wheel hop will be a big help IMV.
Good luck with it regardless.
If that was the case, then I believe what most likely happened was flex between the transmission case and the diff, which broke the ears and that would then obviously cause the output shaft to snap. Another member on here experienced the same thing lately. So, I don't think that the problem is weakness of the output shaft.
I think that the only way to avoid that repeating itself is to install a brace, and I was waiting for ECS to restart production on those, but when I contacted them lately, Chris told me that they had put production of those on hold, because they're extremely busy, it seems. They must be, because I've been trying since the 4 march to get a fuel system and a tensioner ordered, and I still haven't gotten a shipping quote as yet.
The other thing I would do would be to install some Hinson mounts. I have a set of of those, but I haven't gotten around to installing them as yet, because one side looks like it might be a bitch to get at.
Anything that you can do to reduce flex and eliminate wheel hop will be a big help IMV.
Good luck with it regardless.
BIGMAC
03-23-2017, 10:22 AM
#10
Conversely, if the ears snapped off the diff and the diff and the trans separated at the top, that would instantly cause tremendous side loading of the shaft while its rotating, which would snap the sturdiest of shafts like a twig at the bearing. Simple logic, no?
My advice? Get a brace, if you can, even if you have to buy one for another application and modify it to work.
BTW: on the M&Hs, 100 bucks says that if you keep the traction control button in "Competition" mode, you won't get any Active Handling warnings on the DIC either!
03-23-2017, 11:46 AM
#11
Drifting
Thread Starter
Just think about it. What would cause the shaft to snap like that? Under ordinary circumstances, the only forces exerted on the shaft would be torsional. Did it look like it was wrung or sheared by torsional force? Or was it snapped in two? Where did it break? At the back of the housing next to the bearing? What would cause that? And if it did shear/snap off from torsional load, why would that cause the ears to break off your diff?
Conversely, if the ears snapped off the diff and the diff and the trans separated at the top, that would instantly cause tremendous side loading of the shaft while its rotating, which would snap the sturdiest of shafts like a twig at the bearing. Simple logic, no?
My advice? Get a brace, if you can, even if you have to buy one for another application and modify it to work.
BTW: on the M&Hs, 100 bucks says that if you keep the traction control button in "Competition" mode, you won't get any Active Handling warnings on the DIC either!
Conversely, if the ears snapped off the diff and the diff and the trans separated at the top, that would instantly cause tremendous side loading of the shaft while its rotating, which would snap the sturdiest of shafts like a twig at the bearing. Simple logic, no?
My advice? Get a brace, if you can, even if you have to buy one for another application and modify it to work.
BTW: on the M&Hs, 100 bucks says that if you keep the traction control button in "Competition" mode, you won't get any Active Handling warnings on the DIC either!
You are making some great points.
BIGMAC
