Tiptronic issues, rough downshifts with occasional jolts

[ze_german]

Morning Guys.

I'm having problems with my tiptronic box, especially on downshifts.

Check this out:
- when I leave the car standing for a couple of hours and I turn the key to ignition (so no ON yet), I can hear a knocking sound for about 2-3 seconds
- when the car is warm and I turn it on, this knocking sound isn't there
- when there is no load on the transmission and I shift from 3nd to 2nd, there is a "bonk", a jolt, and it's quite hard
- when I let the car downshift on it's own in Manual mode, there is a little jolt when shifting down, especially noticeable in the lower gears 3-2-1
- upshifts are normally silky smooth but sometimes it feels like the "clutch" takes it's time, so when you let go and then accelerate again it doesn't grip as quickly as it should, the needle goes up and then down

If I had a manual box I would say the clutch has issues but since this is my first auto I have no idea. Oil pressure maybe?
I just talked to my mechanic 1 week ago to do a transmission service with full oil change.

Any help would be appreciated.

P.s. forgot to mention that these problems aren't always there, they are intermittent, and the car brought me to the Grand Canyon and back (1500miles) this weekend with no further issues except the above mentioned. Cruising down the highway doing 80 feels perfectly normal.

[Porschephd]

Couple of things come to mind here. The key "on" no start may be the fuel pump priming, mine did this from time to time and the filter was dirty. I would get someone to turn the key on and standout side the car and try to isolate where it is coming from. There are several things that kick in when you turn the key on. I don't think it is related to the tranny.

The bonk or jolt is probably your engine/motor mounts and snub mount. I have had this issue for a while. I did a tranny flush this weekend and it helped some, but what I found was the tranny mounts (both) are popped. There is dried fluid all over the cover and mounts. Also my right engine mount is shot. So when the car down shifts that slack is throwing the tranny and motor around. I would suspect you are getting the same thing. I also notice that when I downshift hard on the hwy I get a huge bonk which clearly indicates movement. I would pull the covers off and look to see if you can see a trace of fluid, wet or dry.

[ze_german]

Good point. The knocking sound def comes from the mid/back, I will ask a colleague to help me out.

Yes, my right engine mount is shot too (throws solenoid error in vag-com). I will ask my mech to check out the mounts on the tranny too. Like I said, the car runs fine for the rest, highway driving went beautiful (except for some people in Arizona who clearly have no concept of keeping right) and upshifts in the higher gears are smooth as ever.

Couple of things come to mind here. The key "on" no start may be the fuel pump priming, mine did this from time to time and the filter was dirty. I would get someone to turn the key on and standout side the car and try to isolate where it is coming from. There are several things that kick in when you turn the key on. I don't think it is related to the tranny.

The bonk or jolt is probably your engine/motor mounts and snub mount. I have had this issue for a while. I did a tranny flush this weekend and it helped some, but what I found was the tranny mounts (both) are popped. There is dried fluid all over the cover and mounts. Also my right engine mount is shot. So when the car down shifts that slack is throwing the tranny and motor around. I would suspect you are getting the same thing. I also notice that when I downshift hard on the hwy I get a huge bonk which clearly indicates movement. I would pull the covers off and look to see if you can see a trace of fluid, wet or dry.

[R&Cs4]

The sound you get when turning to ignition may also be the throttle body aligning...I'd check that out to ensure it's functioning properly.

[Scotty@Advanced]

When is the last time you had your trans serviced?

[ze_german]

Never, I bought the car 10 month ago with 78k miles on it.
I had the first trans service scheduled with my mech for end of october. But I just called him and we are going to to it this weekend. The car has done 89k miles now.

When is the last time you had your trans serviced?

[ze_german]

Update:

Just listened under the car and the knocking sound def comes from the tranny. Also there was a puddle of fluid, it's dripping down somewhere in the tunnel, can't see where.
Going to my mechanic today to check the leak.

[Fade2Black]

Do your rear differential fluid also.

[Porschephd]

Never, I bought the car 10 month ago with 78k miles on it.
I had the first trans service scheduled with my mech for end of october. But I just called him and we are going to to it this weekend. The car has done 89k miles now.

That’s a new one for me. I can't think of anything in the tranny that cycles with just the key on. Unless a solenoid is stuck and popping back in place but would think that is highly unlikely. Although I have learned working on Porsches and Audis not much surprises me anymore. Keep us posted.

[ze_german]

It just occurs when the car is sitting for a couple of hours and is cold. I was at my mech yday eve and we checked for leaks or other loose mounts but everything seemed within normal tolerances, except my rear diff mounts (which i will replace with polyurethane ones) but that wouldn't cause this problem.

We will do a full trans service and fuel filter and listen to the car on Saturday. There are no error codes whatsoever.
I will keep you posted.

That’s a new one for me. I can't think of anything in the tranny that cycles with just the key on. Unless a solenoid is stuck and popping back in place but would think that is highly unlikely. Although I have learned working on Porsches and Audis not much surprises me anymore. Keep us posted.

[ze_german]

Update:

Did the tranny service and changed the fuel filter at my mechanic saturday.
Oil from the tranny looked dark and old, was probably never changed in the 89k miles the car has on it. The fuel filter only worked on one line, the center line was totally blocked. My guess is that it has never been changed before too.

Now with the new filter I can notice a little smoother run of the engine. Seems less rough but that can be my imagination. Also the knocking sounds has not returned so far!

For the tranny, although the oil most certainly helped a little in smoothness, every downshift from 3rd to 2nd results in a noticeable jolt in the transmission line, especially under braking!
In S mode the tranny feels rough and shifts are hard, I keep it in Manual most of the time so it shifts less in the lower gears.
Dunno what to think of this, there are no error codes and 4-5-6 feel absolutely fine, lower gears are rough and not fun at all.

[JayDog747]

Have you checked the rear diff mount? I replaced the one in the A at 75k. Same symptoms, knock in the lower gears not much in the higher ones. I have one waiting for the S for when it goes.

[8cylinders]

Happened to me and my tranny went boom! Just got it back after a 10k rebuild

[ze_german]

:( Do you mean $10k? I thought a new one is only $8k. That sucks!

Happened to me and my tranny went boom! Just got it back after a 10k rebuild

[ze_german]

If it really gets to the point that i need to replace the tranny, I see 2 of them on the german ebay for €1100 ($1400) and €1300 ($1664).

Helps being a german and knowing people who will pick it up for me and send it over.

[scamsel]

hi ze, so you didn't notice much of a difference from the tran service in shifting response, just a little 'smoother' it felt to you? can you elaborate?

did you also replace the rear diff fluid?

[ze_german]

Ok. The initial 'feeling' after the oil change was a noticable smoother operation all around, except that the 'jolt' from 3rd down to 2nd gear became always present.

1. Every time I brought the car to a stop I could feel the 3rd to 2nd downshift, like a slack in the drive train
2. The worst it was felt when under acceleration and the downshift to 2nd (horrible jerk) but also when there was no load on the transmission at all

Now, last Friday a funny thing happened. I was blasting down the 22 for 20 minutes, going home from work, it was 105-110 degrees outside. While coming to a stop at the offramp I hardly noticed any downshift jerk at all. It became a lot smoother, like something that didn't work before suddenly worked again. Now, when I downshift from 3rd to 2nd under braking, keeping the revs above 2000, there is NO slack or jolt whatsoever. Under acceleration it is still there but noticeably less than before.

I would need to talk to a real transmission specialist to understand the inner workings of this tiptronic and figure out whats going on.

I didn't do the rear diff fluid, I need to change my diff mounts and I will do that then.

hi ze, so you didn't notice much of a difference from the tran service in shifting response, just a little 'smoother' it felt to you? can you elaborate?

did you also replace the rear diff fluid?

[WolfS4]

I held off on saying it earlier, but have you ruled out the MAF? A faulty MAF could cause rough shifts. Just something else to explore...

[ze_german]

Upshifts are silky smooth and downshifts too, except 3rd to 2nd gear. I would expect a faulty MAF to cause all kinds of different results but it's worth checking.

I held off on saying it earlier, but have you ruled out the MAF? A faulty MAF could cause rough shifts. Just something else to explore...

[BBbrandon]

I don't know if you have fixed this problem or not and this may not even be related, but have you ruled out the valve body in the transmission? I am trying to figure out a similar problem in a B6 S4 except it only does it when it is cold and it really isn't a much of a jerk as it is the car randomly shifts... anyway somebody mentioned to me it may be the valve body so just something else to look at if you are still trouble shooting.

[ze_german]

Hi. At the moment I am not troubleshooting it but it sounds like a different issue. Mine shifts perfectly fine except for the jolt when shifting from 3rd down to 2nd under acceleration. Mine felt noticeably smoother after my oil change but i also need to replace my rear diff mount and the 2 bushing on my rear diff carrier. I can't tell you anything until those have been fixed and I know for 100% sure the jolt comes from the tranny.

I don't know if you have fixed this problem or not and this may not even be related, but have you ruled out the valve body in the transmission? I am trying to figure out a similar problem in a B6 S4 except it only does it when it is cold and it really isn't a much of a jerk as it is the car randomly shifts... anyway somebody mentioned to me it may be the valve body so just something else to look at if you are still trouble shooting.

[Caspian]

Hi. At the moment I am not troubleshooting it but it sounds like a different issue. Mine shifts perfectly fine except for the jolt when shifting from 3rd down to 2nd under acceleration. Mine felt noticeably smoother after my oil change but i also need to replace my rear diff mount and the 2 bushing on my rear diff carrier. I can't tell you anything until those have been fixed and I know for 100% sure the jolt comes from the tranny.

I think I'm having a similar problem on a b7 3.2 avant (2006) with 111000Km on it. The thing is, it only happens when the coolant temperature is below the normal (90, or the middle part of the temp gauge). Anything under that, especially on a cold day (near freezing temperatures), and I've basically got to use +- shifter to get the beast to go past 2nd, as well.