Audi A8 Transmission Problems
07-05-2011, 07:00 PM
#13
AudiWorld Super User
07-06-2011, 06:40 AM
#15
AudiWorld Super User
NOT guaranteed, but is the cheapest first step you can take...AND needs to be done anyway, since someone screwed up by adding lots of new atf without changing it....couldn't hurt and if you're lucky, it might help or cure the problem(?).
07-08-2011, 08:32 AM
#17
AudiWorld Super User
Try to find the correct problem, as I read about all the fluid changes up here, most of fluid changes are desperate hope to fix your problems and many will help you to ruin your transmission faster. Think with a logic, all the oil go through these little passages controlled by electronic valves, dirty oil will not stop the oil from going through these "veins". The procedure of changing the oil is complex, not really documented well, do it blindly will definitely kill the transmissions like many up here did.
Cheers and good luck,
Louis
Cheers and good luck,
Louis
07-08-2011, 08:46 AM
#18
At any rate I feel draining and adding some new ATF at some point in the trans' life is better than leaving the old fluid in by it's lonesome.
I also agree that it is possible that a complete fluid change might speed the trans' demise as the fresh fluid cleans out the crud that is holding things together (or more likely the crud has altered the viscosity and slipperyness of the fluid and allows the trans to work in a degraded state.)
The dirty fluid is full of metal and clutch material and is going to act differently from new fluid.
One of the keys to long oil life is keeping the additives working so they can react to chemical changes. IMO people who run engine oil for a long, long time get the additives refreshed by top-ups and filter changes (taking some oil out with the old filter.) My uninformed inclination would be to add at least a couple quarts of fresh fluid if the filter is changed in this case. I would not suggest a full drain of the TC.
07-08-2011, 12:28 PM
#19
AudiWorld Super User
My feeling is that changing some of the fluid refreshes the additive package in the fluid and is beneficial up to a point. If the filter is clogged or clogs, yes that's a huge problem but if not I do not feel it's a big deal to leave it in place. Granted there is no way of telling how close to clogged it might be.
At any rate I feel draining and adding some new ATF at some point in the trans' life is better than leaving the old fluid in by it's lonesome.
I also agree that it is possible that a complete fluid change might speed the trans' demise as the fresh fluid cleans out the crud that is holding things together (or more likely the crud has altered the viscosity and slipperyness of the fluid and allows the trans to work in a degraded state.)
The dirty fluid is full of metal and clutch material and is going to act differently from new fluid.
One of the keys to long oil life is keeping the additives working so they can react to chemical changes. IMO people who run engine oil for a long, long time get the additives refreshed by top-ups and filter changes (taking some oil out with the old filter.) My uninformed inclination would be to add at least a couple quarts of fresh fluid if the filter is changed in this case. I would not suggest a full drain of the TC.
At any rate I feel draining and adding some new ATF at some point in the trans' life is better than leaving the old fluid in by it's lonesome.
I also agree that it is possible that a complete fluid change might speed the trans' demise as the fresh fluid cleans out the crud that is holding things together (or more likely the crud has altered the viscosity and slipperyness of the fluid and allows the trans to work in a degraded state.)
The dirty fluid is full of metal and clutch material and is going to act differently from new fluid.
One of the keys to long oil life is keeping the additives working so they can react to chemical changes. IMO people who run engine oil for a long, long time get the additives refreshed by top-ups and filter changes (taking some oil out with the old filter.) My uninformed inclination would be to add at least a couple quarts of fresh fluid if the filter is changed in this case. I would not suggest a full drain of the TC.
The additives of which you speak are mostly the detergents of which I speak (those that break loose more debris which has NOWHERE to go but the filter...it ALL passes through the filter)..the rest is mostly just oil, which in a correctly working transmission does not alter significantly in viscosity or lubing ability (NOT it's most significant job) ...not the same type oil as in an engine and nowhere close to the same duties performed. The energy of a transmission is provided by the engine...most of the power transfer (85%) is through the TC by fluid pressure/resistance and centrifugal force...small changes in viscosity do not change this operation significantly. The other purpose of the oil (MUCH more significant than lubing)is producing hydraulic pressure to feed the TC, shift gears and allowing clutches to engage. The only things that would hinder this pressure from being produced is a clogged filter, low atf, a pump failing (maybe due to being overworked by a clogged filter) or bubbles in the fluid (NOT a symptom or product of old oil)...bubbles would only be caused by another problem such as overfill, etc..
I agree that there all 2 schools (maybe 3?) of thought, both with merit: NO maintenance at at all, so long as no symptoms arise...and logical limited maintenance, esp if any symptom arises.
My main point is that introducing a significant amount of new atf alters things, which ABSOLUTELY requires a new filter. It is not just a complete flush that breaks loose long term debris build up (some of which can be beneficial on worn trans parts)...it is new atf, chocked full of detergents ("additives"). It is terrible practice and illogical to do one without the other.
Topping off with a small amount is one thing. Changing all that drains out without a filter change does NOT improve anything...it complicates it and is guaranteed to continue and increase the restriction of much needed hydraulic pressure. Adequate lubrication (job # 3)is not provided by a precise viscosity or additive balance, but ALL operations are totally dependent on an unrestricted filter, which not only allows full pressure but also continues to clean the atf for free movement of the valves which distribute that pressure.
Last edited by silverd2; 07-08-2011 at 06:16 PM.
07-09-2011, 05:35 AM
#20
Old Audi Owner
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All good points. I will say that in 30 plus years as an auto tech I've never ever seen an automatic transmission that benefited from no preventative maintenance. If you do a full flush and the tranmission dies it was going to die shortly anyway. Past experience shows that without proper maintenance you WILL get less life out of your automatic. Full flushes are important even with high miles. I've flushed many high mileage autos including my own and have never had a problem related to the flush. And certainly changing part of the fluid without changing the filter is a exercise in futility. Anything that comes loose due to the detergent in the new fluid is going to end up in your already plugged filter. Then you've almost certainly doomed your transmission.
Through research and personal experience, I must disagree with most of that.
The additives of which you speak are mostly the detergents of which I speak (those that break loose more debris which has NOWHERE to go but the filter...it ALL passes through the filter)..the rest is mostly just oil, which in a correctly working transmission does not alter significantly in viscosity or lubing ability (NOT it's most significant job) ...not the same type oil as in an engine and nowhere close to the same duties performed. The energy of a transmission is provided by the engine...most of the power transfer (85%) is through the TC by fluid pressure/resistance and centrifugal force...small changes in viscosity do not change this operation significantly. The other purpose of the oil (MUCH more significant than lubing)is producing hydraulic pressure to feed the TC, shift gears and allowing clutches to engage. The only things that would hinder this pressure from being produced is a clogged filter, low atf, a pump failing (maybe due to being overworked by a clogged filter) or bubbles in the fluid (NOT a symptom or product of old oil)...bubbles would only be caused by another problem such as overfill, etc..
I agree that there all 2 schools (maybe 3?) of thought, both with merit: NO maintenance at at all, so long as no symptoms arise...and logical limited maintenance, esp if any symptom arises.
My main point is that introducing a significant amount of new atf alters things, which ABSOLUTELY requires a new filter. It is not just a complete flush that breaks loose long term debris build up (some of which can be beneficial on worn trans parts)...it is new atf, chocked full of detergents ("additives"). It is terrible practice and illogical to do one without the other.
Topping off with a small amount is one thing. Changing all that drains out without a filter change does NOT improve anything...it complicates it and is guaranteed to continue and increase the restriction of much needed hydraulic pressure. Adequate lubrication (job # 3)is not provided by a precise viscosity or additive balance, but ALL operations are totally dependent on an unrestricted filter, which not only allows full pressure but also continues to clean the atf for free movement of the valves which distribute that pressure.
The additives of which you speak are mostly the detergents of which I speak (those that break loose more debris which has NOWHERE to go but the filter...it ALL passes through the filter)..the rest is mostly just oil, which in a correctly working transmission does not alter significantly in viscosity or lubing ability (NOT it's most significant job) ...not the same type oil as in an engine and nowhere close to the same duties performed. The energy of a transmission is provided by the engine...most of the power transfer (85%) is through the TC by fluid pressure/resistance and centrifugal force...small changes in viscosity do not change this operation significantly. The other purpose of the oil (MUCH more significant than lubing)is producing hydraulic pressure to feed the TC, shift gears and allowing clutches to engage. The only things that would hinder this pressure from being produced is a clogged filter, low atf, a pump failing (maybe due to being overworked by a clogged filter) or bubbles in the fluid (NOT a symptom or product of old oil)...bubbles would only be caused by another problem such as overfill, etc..
I agree that there all 2 schools (maybe 3?) of thought, both with merit: NO maintenance at at all, so long as no symptoms arise...and logical limited maintenance, esp if any symptom arises.
My main point is that introducing a significant amount of new atf alters things, which ABSOLUTELY requires a new filter. It is not just a complete flush that breaks loose long term debris build up (some of which can be beneficial on worn trans parts)...it is new atf, chocked full of detergents ("additives"). It is terrible practice and illogical to do one without the other.
Topping off with a small amount is one thing. Changing all that drains out without a filter change does NOT improve anything...it complicates it and is guaranteed to continue and increase the restriction of much needed hydraulic pressure. Adequate lubrication (job # 3)is not provided by a precise viscosity or additive balance, but ALL operations are totally dependent on an unrestricted filter, which not only allows full pressure but also continues to clean the atf for free movement of the valves which distribute that pressure.