PaulW

I've been mentally watching what my tranny does on coast down during the "thump" and during the "hunt" at 45 MPH.

I keep coming back to the clutch is dropping out and then picking back up again during the "thump", and the "hunt" it just seems like it can't decide on a gear.

I have quite a bit of experience in hydraulics.....and I was trying to figure out how the clutches could be dropping out....but if the pressure is getting short circuited because it leaks by the manifold before it can get to the clutch.....it sure makes perfect sense.

I had not considered this before.....was focusing on fluid pressure at the pump and electronics....

With both of those being good, this makes perfect sense.

It won't cost but $200-$300 to try our theory out (good thing my car is paid for)....and if it fixes my transmission, it will be cheap! If not, I've just done another fluid and filter change.

But I have a very good feeling about this.....

CaseyH

If you have success, I won't be far behind. How do you think this will affect longevity?

tozoM8

These channels transfer the fluid pressure to the clutches, when you take off your foot of the pedal, the pump is not creating as much pressure. These channels suppose to hold the pressure. If they don't, when you step on the gas again, in the first second the pump has to built up the pressure before your clutch can transfer the power to the drive train. That is why your rpm goes up then falls back. Every time it does that, your clutch is slipping a little. Since mine is fixed, I can feel that it has more engine brake too, the clutch is always closed and ready to go.

PaulW

Maybe next week, maybe I could come out your way this weekend to get the filter kit?

Or maybe you could drop it off at the tranny shop if it's not out of the way.

I think you paid about $30 with shipping for it....I can just PayPal you.

I'm excited, I think it might just work!

skiracer

which in this case means that as long as the sealant is in contact with air (contains free oxygen), it will NOT cure or harden. Once the part is assembled and the sealant is trapped between the parts without any air, it will cure. Loctite works like this- stays liquid until you assemble the parts, then hardens between the threads.

PNW_A8

Hello all,

I've spent quite a bit of time searching and going over every thread related to this transmission hunting issue, as I, of course, have the same problem.

Just bought a 99 A8 with 112k miles on it. I did a flush and filter, with no significant change. The transmission shifts perfectly for the first mile or two when cold, and then acts up. My symptoms are as follows:

-Hunting
-Slight slip with each gear change
-Occasional hard shift into gear after letting off the throttle

One thing I did notice yesterday, that I had not yet read at all, is that when coming down a mountain and putting the trans into neutral to coast for a while, upon re-engaging Drive, the transmission was in a much lower gear than it should have been for the actual road speed. When shifting back into drive, the rpms went up past 4000, and then the transmission immediately found the correct gear.

So, has anyone else done this VB gasket fix? Has it worked? TozoM8, did it hold up?

I've noticed that many of your posts about solving this trans issue are from 04-05, and you are now doing the manual swaps... did you end up giving up on it?

Cheers

twentysevenlitres

Why would you do this?
Your car coasting down a hill off throttle in gear uses absolutely no fuel (zero, zip, nada).
Out of gear, the engine goes to idle and uses fuel.

It hasn't been economical to put a car in neutral down hill since the early 90s.

Nice thread resurrection btw

PNW_A8

I was not aware that all fuel to the moor is shut off during an engine braking situation. Good to know.

Desperate times call for desperate measures... like reviving 10 year old threads for my first post.

PNW_A8

So many threads with promising solutions, but rarely a conclusion posted.

https://www.audiworld.com/forums/showthread.php?t=1744827&page=2