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Discussion Starter · #1 ·
Hi guys!
I was wondering if someone heard or experienced this kind of weird problem with the 2.5T engine wich is also available on P1s T5s, P3s under different badges and engine type, etc.

I now have my 08 S80 2.5T Geartronic (TF-80SC) wich I absolutely love but since last summer I'm experiencing this super-weird symptoms.
It all started with a hot day and after a bit of highway driving I noticed that requesting a down-shift for example from 100 kph to 130 kph resulted in a "slam shift" with a bang like the engine stalled for a second and restarted instantly. After this one episode I believe the car starts to overfuel or something because the MPG is horrendous. Also, I have to slowly accelerate in order to avoid sudden down-shift because the car feels like it's going to rip its engine mounts apart (if not damaged already) and destroy the gearbox, so I have to drive the car like old people :). The MPG get very bad and it seems to behave like this only on high speeds, like over 80 kph, no ideea why.

Here's the fun part. It seems to only behave like this after highway driving, after all temperatures get optimal (gearbox 75 - 90 degrees, coolant 75 - 90 degrees) and only on high speeds. It doesn't do it when cold, when city driving or after the car sat for a while. The MPG though is worse on slow speeds, economical driving and much better at highway speeds, driving aggresively, kick-downs, etc wich shocked me because it didn't make any sense. I did some tests with VIDA, no errors on ECM or TCM, except one time I found ECM-P061A68! MAF seems to read as stated in VIDA, spark plugs OEM replaced, did the VVT tests on both intake and exhaust with VIDA, resulted ok. I have a clean new air filter, ordered a new fuel pressure sensor as these engines have a thing with them. I use the car almost as a daily driver and drives great, gearbox is very smooth, had the oil replaced with VIDA method a few months ago, manual shifting is so smooth you can't really tell when it happens unless you watch the indicator on the dash. I don't suspect the gearbox as the culprit. Even if the gearbox had some issues it wouldn't explain the bad MPG at low speeds\economical driving.
I'm going to check the MAF, get new spark plugs and install a new pressure sensor in the next few days.

Maybe some of you guys heard\had experienced this kind of issue and provide further info!
 

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Are you getting any Check Engine on the console? If you're using too much gas because it's running rich, I would expect the O2 sensors to pick this up and throw an engine code. How many miles on this car? Is it AWD or FWD? The "slam shift" sounds pretty bad, like you don't feel you can experiment with the conditions that cause it. Is this only on a kick-down shift? Does the RPM jump higher like what happens when you floor it (kick down shift)?

What if you drive at high speeds using the manual Geartronic shifting? Any problems when you accelerate? I think "kick-down" shifting is disabled when in manual shift mode.

Hoping you'll share the post-mortem when this gets figured out.
 

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Discussion Starter · #3 ·
Are you getting any Check Engine on the console? If you're using too much gas because it's running rich, I would expect the O2 sensors to pick this up and throw an engine code. How many miles on this car? Is it AWD or FWD? The "slam shift" sounds pretty bad, like you don't feel you can experiment with the conditions that cause it. Is this only on a kick-down shift? Does the RPM jump higher like what happens when you floor it (kick down shift)?

What if you drive at high speeds using the manual Geartronic shifting? Any problems when you accelerate? I think "kick-down" shifting is disabled when in manual shift mode.

Hoping you'll share the post-mortem when this gets figured out.
Hi,
No check engine light, no DTCs regarding O2 sensors, ecm, gearbox, etc. In fact, I didn't see the check light on this car since I own it :). Car is FWD. This "slam" is pretty violent yes and it's not something I want to repeat too often. It does it whenever I put a load on the engine, not kick-downs but accelerating "normally" wich causes a down-shift, harder on aggressive acceleration and I can avoid it if sloooowly push it. The RPM doesn't jump erratically. I'll try and reproduce the symptoms and see what it does in manual only mode.

New fuel pressure sensor arrived today, will install it and see if anything changes.

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Get the shift solenoid replaced and swap fluid and make SURE it is at the proper level. Dirty fluid over years of
driving can sludge up these solenoids causing all sorts of problems. One of many reasons that LIFETIME fluid is
a load of crap.
 

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Get the shift solenoid replaced and swap fluid and make SURE it is at the proper level. Dirty fluid over years of
driving can sludge up these solenoids causing all sorts of problems. One of many reasons that LIFETIME fluid is
a load of crap.
Which shift solenoid should he replace? there are 8 of them on the valve body.
 

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The one for whichever gear is slam shifting of course. Hook it up to a scan tool to check line pressure and or solenoid pressure. Could be a clog somewhere since it’s only doing the slam shift under high load.


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