Transmission thump part 2 ( I do not want this to get lost at the bottom of the page ).
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Transmission thump part 2 ( I do not want this to get lost at the bottom of the page ).
Paul, it may seem like a coincidence that my thump started at the same time as my fluid change.
This is my argument against that.
I live in a very very hilly part of NY. I can not travel a mile without coasting down a hill. I have owned my A8 over two years of driving up and down these hills and never had a thump EVER. Within 2 minutes leaving this shop that changed the fluid/screen last week, I had my first thump and it scared the crap out of me ( never feeling this before ). Since that fluid change I get thump down every hill usually twice.
This seems to point directly at the fluid change. Either the fluid, way it was filled, etc. I have coasted down too many hills to settle on coincidence.
I think we have to open our minds more on this.
Living where I do, and being in the line of work I am, I am not going to live with this. If I do not figure this out I am doing one of three things. Put a manual trans ( and the other related parts ) in the car. Sell it and get a S8. Or sell it and get a lexus.
Speaking of, does anyones S8 show any of the same problems of the A8?
Thumping?
Hunting?
This is my argument against that.
I live in a very very hilly part of NY. I can not travel a mile without coasting down a hill. I have owned my A8 over two years of driving up and down these hills and never had a thump EVER. Within 2 minutes leaving this shop that changed the fluid/screen last week, I had my first thump and it scared the crap out of me ( never feeling this before ). Since that fluid change I get thump down every hill usually twice.
This seems to point directly at the fluid change. Either the fluid, way it was filled, etc. I have coasted down too many hills to settle on coincidence.
I think we have to open our minds more on this.
Living where I do, and being in the line of work I am, I am not going to live with this. If I do not figure this out I am doing one of three things. Put a manual trans ( and the other related parts ) in the car. Sell it and get a S8. Or sell it and get a lexus.
Speaking of, does anyones S8 show any of the same problems of the A8?
Thumping?
Hunting?
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same experience here...
I'm a owner of 97 A8 with just over 100k on it. Three weeks ago started to get some whinning noise from under the hood and Paul gave me advice to change transmission oil and filter. I did, and hell, was the old oil and filter in bad condition! After replacing with new, I noted the difference in tranny behavior (thump, some rough up and downshiftings). It wasn't like that before I started the job! I did everything right I believe during the service (it is pretty hard to mess up such an easy service). The only thing I was blaming those thumps for - is myself. I thought that driving with that noise (about 140 miles, while I was waiting for parts), I did the damage to the cavitating pump. May be I did, may be it is something also.
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My fluid was not low, or leaking. I did the service only because it was up on the lift for the oil..
.... change and I really trusted the new shop i was in.
Again, this seems to be caused by something other than coincidence.
Again, this seems to be caused by something other than coincidence.
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The pump has nothing to do with the hunting and the dropout.
It supplies much higher pressure than the tranny needs. The tranny needs around 100 psi pressure for forward gears, but it needs 180-190 psi for reverse. So if you don't have problem with your reverse, then your pump is just fine. As I mentioned earlier, that pump is a monster. It should be able to push 1000 psi easy. It has a regulator right by the pump to dump back the extra pressure. After the regulator it goes to the valve body ( still over 200 psi) and the main pressure regulator valve controls the pressure. My pump was cavitating when I bought the car and I drove it for weeks before the first fluid change. It was loud even whet the car was hot. After the fluid change it was quiet again. When my valve body cracked, it went into limp mode right away. Since there is no fluid pressure control in limp mode, the pressure from the pump cracked my clutch A housing like a pretzel. So I wouldn't worry about the pump much.
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Fluid level?
Is it possible the shop underfilled it and now it acts up when you go up and down hills? Just a thought.
I use to get the thumping at every stop sign. After the fluid change it went away. Now I only get it on the highway in D when the TC unlocks.
Does your problem show up if you use Tip?
I use to get the thumping at every stop sign. After the fluid change it went away. Now I only get it on the highway in D when the TC unlocks.
Does your problem show up if you use Tip?
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My problem shows up only, and every time I go down a hill, coasting, with my foot off of the gas, or
foot off of the brake.
If I am on the gas even a TINY bit, it does not do it. If I am on the brake at all it does not do it. Only during coasting down hills.
If I am on the gas even a TINY bit, it does not do it. If I am on the brake at all it does not do it. Only during coasting down hills.
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Re: Since you have another few cars to drive, you should work on the manual conversion.
I would love to, but do like to be lazy on long drives. When I want to drive fast and sporty, I do not drive the A8.
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That's consistent with what we know.
(Tozo correct me if I'm wrong) The TC is locked under acceleration, now if we could figure out why it unlocks so violently.
I wonder how much it would be to have someone find a 6 speed that would fit in our cars.
I wonder how much it would be to have someone find a 6 speed that would fit in our cars.
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Ok. It's called shift kit.
It's an upgrade for the valve body. Certain springs are getting too soft after so many years of heat and TC lock/unlock. If you monitor your tranny, you can see that the TC pressure regulator valve works just fine, but the TC lock is still delayed.