Transmission Malfunction Codes and Related Issues

[Panzer]

Hey everyone, first off, thanks for looking.

Backstory:

Bought our 2013 Q5 3.0T Premium Plus S-Line 3 years ago. (01/2018). It had 99k miles on it at purchase. (Unknown to me if the OEM trans fluid was changed prior.)

Drove the car and loved it for the past 3 years.

Recently we have started to develop transmission issues and ended up buying a 2019 Q3. To keep the story short, it's quite lackluster going from the 3.0T to the 2.0T. My wife primarily drove the Q5, and it was our family vehicle. I travel out of town for work so I can't risk her being in a vehicle that would potentially leave her and my children stranded somewhere.

So here's the current issue.

When starting the vehicle, and this seems more prevalent when it's cold, if you shift to drive or reverse, the transmission doesn't engage though the MMI shows it as such. Putting it in D, sometimes it will show it shift directly to 3rd gear (I have the gear display enabled in vagcom). The car sits still as if it's in neutral.

Also, we would get error messages saying "Transmission Malfunction. Limited Driving Functionality" followed by "Transmission Malfunction. No Reverse Gear Available."

The only way to resolve the issue was to shift to park and shut the vehicle off. Upon restarting, 90% of the time it is fine. More recently it has continued to act up more and more though, with the above errors and issues repeating themselves 4-5 times before being resolved by shutting it off and restarting. (EDIT: It only ever does it when cold, only in our driveway. Never once when it was anywhere else, only after it sits overnight and on the first initial start up after an extended time of being parked. We have a remote start installed and used that a lot to start it and get it up to temp, and that seemed to alleviate the issues for the most part.)

It's also important to note that the car currently has 133k miles on it, and at around 130k miles I did a transmission fluid change and filter change. We were getting the occasional rough shifting when cold and that was about it. The error had occurred a few times prior to the fluid change but now it is coming back more and more frequently. I had used the Liqui-Moly fluid and Meyle filter available in the trans service kit from ECS. Now I'm slightly regretting that decision, curious if it has caused more issues than good.

Upon scanning with vagcom, the following automatic transmission codes were present. (I have the full scans available on my laptop if anyone would like to help and see them, I'm posting from my phone currently and retyping the info.)

3 fault codes found:

-P2701 Transmission Friction Element / Clutch B
-P0730 Incorrect Gear Ratio
-P0780 Shift Error

I have searched and tried reading what I could about these three codes in conjunction with the ZF8 transmission but with no luck specifically to those codes especially together and in any way related to the Q5 platform.

Lastly, for fear of potentially overfilling the transmission, I jacked the vehicle up and got it to 40°C and pulled the plug on the trans to check the fluid level. Only about half a cup of fluid came out, but what did had what looked like a fair amount of metal shavings in the fluid. I'm afraid that either the new fluid agitated the metal shavings that were potentially trapped in the transmission and dislodged them, causing more issues, or that not using the ZF LifeForce 8 fluid and instead, the Liqui-Moly version had caused issues.

Ultimately, the vehicle was set to be traded in, and I opted not to as I still have a loan out on the vehicle. I daily a B8 A4 and would prefer to sell the A4 (which is paid off and would cover the remaining amount due on the Q5) and keep the B8.5 Q5 if possible, but fear there's too much transmission damage done already. Im fearful of needing to sink $2-$3k into buying a used transmission/having our transmission rebuilt for a vehicle only worth around $8k currently. My A4 is bagged and I had planned to swap the airride to the Q5 and drive it to and from work instead.

Does anyone have any experience with the codes above or knowledge about similar transmission issues/failure? What would you do if you were in my shoes?

Sorry for such a long post. Anyone who read it all, thanks for reading. I genuinely appreciate any help I get.

[djn876]

I don't know if the liquimoly meets the ZF spec or not, it says it would be a replacement part for the Audi number on their site and hopefully ECS wouldn't sell it like that if it didn't, but metal shavings are not good and that trans probably needs a rebuild. :(

You could try draining it, flushing, draining, a few times and see if you can get all of the crap out of there, but there are so many small passages and things that could be clogged if there is a bunch of junk in there. It could also just be that the friction elements in those clutches are toast. They also use steel rings in the clutch pack and if those are seeing wear, it could be the cause of the shavings.

How was the service performed, did you DIY or have it done somewhere? Was the ZF procedure followed when filling? It sounds like there was enough fluid in there, being a little high like that probably isn't an issue.

Here is what the manual says for the fault codes:

P2701:

Transmission Friction Element "B" Apply Time Range/Performance

Rationality check

Ratio detected is outside of defined limits. Fault code for up to 3 corresponding clutches may be set. Additional rationality checks using a substitute gear(s) is initiated. Depending on the behavior in the substitute gear(s), an additional fault code for only one or two clutches may be set to better distinguish the root cause of the problem.

GENERAL ENABLE CONDITIONS:
• oil-temperature > 0 °C
• engine speed > 400 rpm or if engine speed < threshold. output speed > 2500 rpm
• input speed > 0 rpm
• transmission lever position D or R
• timer elapsed > 200 ms
• no malfunction in input speed signal
• no malfunction in output speed signal
ADDITIONAL ENABLE CONDITIONS FOR GEARSHIFTS:
• output speed gradient > CC Ratio XYZ xy rpm
ADDITIONAL ENABLE CONDITIONS FOR ENGAGING GEARS:
• input speed gradient > 5000 rpm
• throttle > 5.09803921568628 %

• 3 times
• 30 ms

• 2 DCY
• continuous

P0730

Incorrect Gear Ratio

This one reads pretty much exactly as above. Since the clutch will engage to determine the gear ratio, it makes sense that these would go together.

P0780

Shift Error

Rationality check

While shifting from gear X to gear Y the ratio is outside the defined limits is detected.
> gear X ratio + CC
Ratio THUP x + CC
Ratio OFTHUP xy
OR
• actual ratio < gear Y ratio - CC
Ratio THLO y - CC
Ratio OFTHLO xy

UPSHIFT
• shifting from gear X to gear Y in progress
AND
• output speed >= 50 rpm
DOWNSHIFT
• shifting from gear X to gear Y in progress
AND
• output speed >= 50 rpm

3 times
30 ms

2 DCY
continuous

[djn876]

It could be the mechatronics too, which can only be replaced, it is a non serviceable part. Again though the metallic pieces are concerning.

Sent from my SM-G988U using Audizine Forum mobile app

[Panzer]

Unfortunately after researching more, that is what I had found too in regards to the fluids. ZF doesn't list any fluids outside of their own proprietary fluid that is supposedly "on-par" with theirs, though a lot of people I'm sure have had to use non-oem fluid especially given the price difference. (It's over double.)

The metal shavings are my big concern now really. I want to flush the transmission as you had mentioned by doing multiple fluid fills and drains, so I might look into that. Just wondering if it's worth buying 9L of the OEM fluid now at this point or use the remaining couple L's I have left over from the original fill. In fairness, my garage isn't totally "sterile" and the small pan I used to catch the fluid coming out wasn't wiped out prior beforehand either, so I don't know if there was dirt present in the pan prior to doing it or not. I also wish I would have strained the fluid also to catch the shavings and look at them more in depth, maybe not suspended in fluid.

We had done the service DIY in my garage, myself, a friend who is a mechanic by trade (not VAG specific but certified) and a fellow SQ5 owner. We used Vag-Com to monitor the trans fluid temp and I jacked all 4 corners up and put it on jack stands so I could run it through gears inside the garage. I had purchased the Schwaben 3L pump from ECS as well to fill the fluid. Filter and gasket as well as bolts were all replaced.

In terms of the multiple drain and fill method, should I be replacing the gasket each time? Also, the filter on the last time I plan to drain and fill? The gasket is only roughly 4-5 months old and has ~3k miles on it since this was done.

The mechatronics was my first concern but as of a few days ago when we checked the fluid and I found what we believed were the shavings, now I'm super concerned about the vehicle. I had been debating just repairing the mechatronics with the help of my mechanic friend but him and I finding the shavings have made me think it might be a feeble attempt to fix it. I know there's a few DIY mechatronics repair kits for under $500, but I don't want to throw money into that if buying a used transmission is going to be the smarter alternative.

Thank you for your help and input this far.

[djn876]

The mechatronics on this trans is not really serviceable so there really isn't going to be much to do there other than replace.

I'm going to use Ravenol 8HP for mine which meets the same spec as the ZF lifeguard fluid. There is a thread 'no thx' started that talks about fluid options and that was one of the recommendations. Either way I'm not sure the fluid would be totally to blame.

It may never have been done before and there was a lot of crap getting washed out. Check out the demystifying the ZF trans thread, pick up some good fluid, and swap out some, drive a little, and do it again. A few hundred in fluid is way less than whatever else you might end up having to do. Sounds like you guys followed the right procedure for the change.

I'd use the same filter and gasket until the final fill, then swap them out. The gasket will likely be OK for a short period and of it weeps a little who really cares if you are going to replace it anyway. There should be any pressure in the pan so it'll be fine.

Sent from my SM-G988U using Audizine Forum mobile app

[Norskie]

Unfortunately after researching more, that is what I had found too in regards to the fluids. ZF doesn't list any fluids outside of their own proprietary fluid that is supposedly "on-par" with theirs, though a lot of people I'm sure have had to use non-oem fluid especially given the price difference. (It's over double.)

Fortunately the ZF lifeguard 8 isn't expensive, it's about $22/L. Much cheaper than the same stuff with an Audi label (about $70/L IIRC what Audi COS charged me).