Diagnosing torsen failure
10-16-2007, 05:47 AM
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Diagnosing torsen failure
At our local autocross this past weekend (and last month), I was experiencing an extreme amount of inside wheelspin on my MY2000. The setup was the same as the other events this year, but the wheelspin was new.
My times are usually within 1.5-2 seconds of 1st, now it's 4+ seconds.
I had known alignment issues last month and got it aligned before this event. The tires were new in March and have been used for ~60 runs.
After the event someone thought that the diff may have gone, but I've alway associated a diff failure with lost of noise and no driveability. There is no noise and when driving on the street it seems to drive fine. Only on the AX course does there seem to be a problem
If only the torsen unit fails, how would someone diagnose it? I checked the honda manual and it tells you how to disassemble, check backlash and assemble, but no mention of checking the torsen unit.
Most of what I've found searching S2KI has referred to catastrophic R&P failure or housing failure with only a few references to torsen failure.
Thanks,
Scott
My times are usually within 1.5-2 seconds of 1st, now it's 4+ seconds.
I had known alignment issues last month and got it aligned before this event. The tires were new in March and have been used for ~60 runs.
After the event someone thought that the diff may have gone, but I've alway associated a diff failure with lost of noise and no driveability. There is no noise and when driving on the street it seems to drive fine. Only on the AX course does there seem to be a problem
If only the torsen unit fails, how would someone diagnose it? I checked the honda manual and it tells you how to disassemble, check backlash and assemble, but no mention of checking the torsen unit.
Most of what I've found searching S2KI has referred to catastrophic R&P failure or housing failure with only a few references to torsen failure.
Thanks,
Scott
10-16-2007, 06:18 AM
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Originally Posted by ScottnHeidi,Oct 16 2007, 08:47 AM
At our local autocross this past weekend (and last month), I was experiencing an extreme amount of inside wheelspin on my MY2000. The setup was the same as the other events this year, but the wheelspin was new.
My times are usually within 1.5-2 seconds of 1st, now it's 4+ seconds.
I had known alignment issues last month and got it aligned before this event. The tires were new in March and have been used for ~60 runs.
After the event someone thought that the diff may have gone, but I've alway associated a diff failure with lost of noise and no driveability. There is no noise and when driving on the street it seems to drive fine. Only on the AX course does there seem to be a problem
If only the torsen unit fails, how would someone diagnose it? I checked the honda manual and it tells you how to disassemble, check backlash and assemble, but no mention of checking the torsen unit.
Most of what I've found searching S2KI has referred to catastrophic R&P failure or housing failure with only a few references to torsen failure.
Thanks,
Scott
My times are usually within 1.5-2 seconds of 1st, now it's 4+ seconds.
I had known alignment issues last month and got it aligned before this event. The tires were new in March and have been used for ~60 runs.
After the event someone thought that the diff may have gone, but I've alway associated a diff failure with lost of noise and no driveability. There is no noise and when driving on the street it seems to drive fine. Only on the AX course does there seem to be a problem
If only the torsen unit fails, how would someone diagnose it? I checked the honda manual and it tells you how to disassemble, check backlash and assemble, but no mention of checking the torsen unit.
Most of what I've found searching S2KI has referred to catastrophic R&P failure or housing failure with only a few references to torsen failure.
Thanks,
Scott
The reason I ask is because with R compound tires some people have had issues with the inside rear tire unloading during cornering, and it sound's to me like that may be what's happening in your case. The Torsen will not stop the inside tire from spinning if it unloads enough, and I think that may be all you're seeing. If so, it's just normal for a Torsen. Before assuming that the LSD is bad I'd do some more testing.
Some of the guys who autocross on R compound tires have found that removing the stock rear anti-sway bar helps keep the inside rear tire from unloading and spinning.
10-16-2007, 08:11 AM
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I've been running A6's all year with the Saner on full stiff. Unless one of the endlinks has failed, the setup has been the same all year.
I will have to double check the endlinks. I thought I would have noticed if it was broken when I was changing tires Sunday, but I know I did not specifically look for it.
I will have to double check the endlinks. I thought I would have noticed if it was broken when I was changing tires Sunday, but I know I did not specifically look for it.
10-16-2007, 09:54 AM
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Well, the manual lists a short test. And I quote...
1. Set the parking brake, and block the rear wheels.
2. Raise the rear of the vehicle, and make sure it is securley supported.
3. With the ignition turned to Lock (0), shift the transmission into 1st gear, and release the parking brake.
4. Rotate either rear wheel by hand, and check that the other wheel rotates in the opposite direction. Check both wheels.
5. If the opposite rear wheel does not rotate, or if you cannot spin the rear wheels at all, the limited slip differential is faulty and should be replaced.
Simple, and about what you would expect.
I would still bet on the front bar but strange things do happen some times...
1. Set the parking brake, and block the rear wheels.
2. Raise the rear of the vehicle, and make sure it is securley supported.
3. With the ignition turned to Lock (0), shift the transmission into 1st gear, and release the parking brake.
4. Rotate either rear wheel by hand, and check that the other wheel rotates in the opposite direction. Check both wheels.
5. If the opposite rear wheel does not rotate, or if you cannot spin the rear wheels at all, the limited slip differential is faulty and should be replaced.
Simple, and about what you would expect.
I would still bet on the front bar but strange things do happen some times...
10-18-2007, 05:32 PM
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OK finally able to get under the car to see if either a sway bar end link broke or try jacking up the rear to test the torsen unit. I skipped the first 5 pages of that section in the manual with the instructions on testing the torsen unit. I've got the manual as a PDF and cant really flip through it so easy.
No broken endlinks and when I spin either wheel forward or backward, the other wheel does not move. Guess I need a new torsen unit.
4 years of autocross, a dozen track days and 75K miles on the gears and bearings
Any recommendations as to whether to replace the whole diff or have it rebuilt? Looks like a new torsen unit is in the ~$800 range. I've got to stay with the Honda setup for stock class and I'm not real interested in going to either street prepared or street mod.
Thanks
Scott
No broken endlinks and when I spin either wheel forward or backward, the other wheel does not move. Guess I need a new torsen unit.
4 years of autocross, a dozen track days and 75K miles on the gears and bearings
Any recommendations as to whether to replace the whole diff or have it rebuilt? Looks like a new torsen unit is in the ~$800 range. I've got to stay with the Honda setup for stock class and I'm not real interested in going to either street prepared or street mod.
Thanks
Scott
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10-18-2007, 06:22 PM
#8
Go with an AP2? Does that keep you in class?
From what I've seen it's usually going to be more cost efficient to get a whole new (or used, but trusted) diff vs. the labor + parts to have someone completely rebuild one (Honda rebuilt mine with new bearings, seals, torsen and r/p for about $2400 covered under HondaCare... then the rebuilt died in 30k miles due to what we believe is a faulty rebuild (specifically mis-shimmed pinion, which went without affecting anything else).
From what I've seen it's usually going to be more cost efficient to get a whole new (or used, but trusted) diff vs. the labor + parts to have someone completely rebuild one (Honda rebuilt mine with new bearings, seals, torsen and r/p for about $2400 covered under HondaCare... then the rebuilt died in 30k miles due to what we believe is a faulty rebuild (specifically mis-shimmed pinion, which went without affecting anything else).
