r/B5Audi • u/Vinnyycentt • 26d ago

fixed boost leak! (2.7t)

I had read somewhere that the stock throttle body boot tends to tear, so I checked mine, and lo and behold, I had a 2-3 inch hole causing a massive boost leak. It took 30 days to get the new TBB, but whatever—once I installed it, the car was way smoother and faster. However, now it seems like the extra power is making my transmission unhappy. I have the ZF HP19 (a crappy auto). It happens mostly when in sport mode, and it feels like the transmission is slipping or unsure of what to do. A flashing check engine light appeared, but it went away every time. However, the ABS and TC lights stay on until I turn the car off and back on. What’s my next step in getting the drivetrain back in tip-top shape? Should I flush and refill the transmission, or could this be something else? This is a 2004 A6 s line with the 2.7t, I know it’s not a b5 but there aren’t many other active communities that are knowledgeable of the 2.7t.

5 Upvotes

100% Upvoted

6 comments sorted by

5

u/BasicMidUsername 26d ago

You should read your codes and then ask again or update this post with that information. I’m sure you’ll get plenty of guesses as to what could be going on but what you need is data to back up the theories.

0

u/Vinnyycentt 26d ago

you guys must have missed the part where i mentioned theres no codes being thrown and the lights on the dash disappears once the car is turned off and then back on again.

2

u/ryebreadinq 26d ago

Manual swap time.

1

u/AtEpic 26d ago

It might just be a bad ground or a loose terminal block, but check your fault codes first, flushing the trans can also fix it

1

u/Vinnyycentt 26d ago

no codes are being thrown and the dash lights go away once i shut the car off and turn if back on again.

1

u/BigMan6656 25d ago

When's the last time the transmission has been serviced? (I. E, filter change and fluid refill). Old or low trans fluid will mess up how they perform.

I got the same transmission and had a cooler line blowout and I got stupid lucky. During the time it leaking, the transmission whined and slipped real bad between gear shifts and I thought for sure my transmission was toast.

I dropped the pan and got everything straightened out, it didn't slip at all. In TIP mode, it felt exactly like my brothers car (same 04 Passat but with a 5 speed).

The longer you wait the worse it will get. If you do drop the pan, you can see the condition of the transmission by inspecting the fluid and the magnets. If the metal on the magnets are gritty instead of a fine paste, there is a good chance your transmission is on its way out and will continue to slip.