S4 B6 Transmission Issue

[pauliusmac]

Hi fellow victims of Audi,

Got a problem, don't know how bad is it, but i'm kind of desperate and looking for some opinions. Got Auto S4 B6. During radiator change forgot one screw for Tranny oil, obviously when started, it leaked out maybe 1/2 quart. Took it too a reputable shop, topped it off and thought all was over. Today, pulling out of the driveway PRNDS lit up. Turned off the car, back on it was gone. Put in R again, PRNDS lights up along with Check Engine. Restarted AGAIN, CEL stays, no other lights remained. Driving in 1,2nd gears, rpm slighty jumping 100-200rpm while it was cold. Going to get the code out, but im wondering what might be the issue. Solenoid? TC? both? Any guidance would be appreciated!

Thanks,

Paul

[pauliusmac]

Forgot to add. I'm from NJ (woodbridge area). Temp in the early morning around 55ish would say.

[Nollywood]

How was it topped up? There's a very specific procedure, if it's not adhered to, the transmission will end up under-filled.

[pauliusmac]

Not sure exactly but he used pressured pump or something like that. And he kept filling it until it started squirting the oil out.

[pauliusmac]

forgot to mention, He said that tranny was overfilled in the first place. so he kept adding as much as possible without overfilling it. I always had this grinding vibrations on some gears on very low rpms when accelerating around 1,100-1,300rpms. dont know if thats related to the current problem though.

[VinnysS4]

Sounds like RPM hunting from the TC

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[pauliusmac]

Biggie?

[pauliusmac]

P0736 is the code

[Velox]

from google:

P0736 Possible causes Low transmission fluid level

Read more: https://www.autocodes.com/p0736_audi.html

[pauliusmac]

Saw that one. Fluid level is fine 99.9% sure. Now the shop is advising to replace mechatronic because separate solenoids are not sold. How much of that is true?

[Fourpoint282]

I had similar issue with mine. The PRNDS is the car going in limp mode. Basically the car is smart enough to keep you from hurting it more. In any case my issue was a solenoid and it cost $6k to fix at Audi dealership. Prob would have cost 20% less at an Indy shop


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[VinnysS4]

Buy a zip kit from sonnax and do it yourself for like $500 with fluid... if it is in fact solinoids in the mechatronic unit (valve body)

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[pauliusmac]

Which one is it? Or i could get a used mecha unit and stick that in. Just no idea how extensive that is...

[VinnysS4]

https://www.sonnax.com/zip_kits

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[lyates1987]

Did he fill it with car on or not? Was tranny temp between 32 and 34 celcius when filling?

[pauliusmac]

Car was on, temperature was checked while filling the temp to make sure we do everything by the books. I have a feeling that previous owner overfilled tranny to cover up issues, now once the fluid is normal, pressures dropped to what should be normal and all the issues came out. Hoping that solenoids and the kit that Vinny recommends will solve it... Very weird honestly. Sometimes PRNDS blinks when backing up, sometimes not. Sometimes feels completely normal, sometimes completely off.. Out of ideas..

[blitz2190]

Car was on, temperature was checked while filling the temp to make sure we do everything by the books. I have a feeling that previous owner overfilled tranny to cover up issues, now once the fluid is normal, pressures dropped to what should be normal and all the issues came out. Hoping that solenoids and the kit that Vinny recommends will solve it... Very weird honestly. Sometimes PRNDS blinks when backing up, sometimes not. Sometimes feels completely normal, sometimes completely off.. Out of ideas..

random though but have you checked your ecu box for water? I'm currently fighting ghost in the wiring with a car that had water damage. Replaced the tcu turns out the plug was beyond repair so now replacing that. I mention that because it was causing random mechanical failure codes and lighting up the prnds.

[VinnysS4]

I have an extra tip tranny if you need ;D

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[pauliusmac]

Mileage? :D thats my plan b. If the whole kit wont help, just swap trannys. And how much $$ u want? :D

[VinnysS4]

Pulled it at 118k and swapped with a manual
I don't know on price. $200? It's just taking up space in my garage lol

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[pauliusmac]

Ok, still no changes. Now discussing whether change solenoids, or just put a used tranny. Same issues. When Cold put in Reverse, PRNDS lights up, 1,2 Gears downshift clunk (like getting bumped). And Fluctuating RPM's ... On the other note, rather paying some shops to do it, maybe anyone in NJ would like to take a look (would pay and get all the parts) . Now just trying to get down to what should i do.

Thanks Everyone who are adding to this thread!

P.S. Hope to get this PITA resolved

[pauliusmac]

UPDATE:

Replaced solenoids, got new code P0706 and the old P0736. Which leads to Transmission Range Sensor.now.. the problem, where to get one lol. The ones in Europa Parts and ECS doesn't fit 100%. Need exactly the one that goes into GUR Mecha unit. Mechanics said that they found some metal debris in the pan, solenoids etc. (probably when the fluids got disturbed, went all over the system) though the fluid itself was fine. So if anyone has GUR gearbox with mecha in it, would give 200-300$ for that "TCU" range sensor.
BIG SHOUT TO EUROPA PARTS, those guys are awesome! Redline Speed Worx, never met such an awesome group of people who helps so much.

@VinnysS4 which Gearbox You had/have? maybe would be willing to open it up? haha

[VinnysS4]

I'd have to check after work

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[pauliusmac]

Awesome! (Whole mecha unit would be better if it was working, if not, then just TCU should do the trick)
Thanks!

[VinnysS4]

Awesome! (Whole mecha unit would be better if it was working, if not, then just TCU should do the trick)
Thanks!

Where on the transmission is thw identifier located?

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[pauliusmac]

Where on the transmission is thw identifier located?

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It should be on tranny itself. Like a bar code. begins with couple numbers and then there is the code. GUR, HHM etc..

[BCsniper]

Yeah if all else fails finding a used tip trans is super easy. Hardest part would be shipping it. There is very little demand for them so many people have one lying around, myself included.

[pauliusmac]

well, i wish i won't need a new tranny. Got used Valve Body unit yesterday, so i'll drop that in, will see what's gonna happen. Makes no sense to open transmission itself it valve body wont solve anything. So getting a new trans won't be an issue. Worst part will be charges for labor....

[pauliusmac]

as much as i love S4 for it's refined power and comfort. The maintenance and fix'es are expensive as hell. And getting parts are major PITA, makes me want to get rid of it and get B8 A4 instead... Timing might be due soon, though no massive rattle on the start <1sec. Labor is the killer in this car. $1300 for transmission swap. Already dropped around 500$ on parts, and got a revised invoice for $1200 labor.... After all this, will reconsider other alternatives and choices for more reasonable DD (though MPG is irrelevant since work is less than 6miles away, thats why i got V8. Chains were considered, but didn't expect tranny or mechatronic to go). Everyone should gather up somewhere and instead of doing Scenery drives, should just fix Timing guides and tensioners lol. I'll keep you guys updated what turns out with this tranny issue.

[pauliusmac]

SOLVED. Replaced whole mecha unit + New solenoids, Oil, filter, and works like new now. Most likely TCU went and started throwing almost random codes. Can't wait to get my car back! Thanks everyone! :)

[pauliusmac]

Ok, another update. It solved the weird shifting but the 1st and reverse still not so good. It works then doesnt. When i stop at red light sometimes PRNDS lights up, have to restart car and everything is back to normal. In the morning got PRNDS as soon as i started the car. And it seems like that reverse ratio code is still there. Also, another random code for Catalytic Converter or O2. Battery is going bad. Slow cranking. Will replace that, but i dont think it will solve those random PRNDS’s. There are no vibrations or noises from trans when it goes to limp, it just does out of nowhere when stopped, though seems to do less when everything comes up to optimal temps. Any ideas guys? I’m thinking about last resort, trans swap. What else could be bad? Valve body with electronics replaced. Replaced solenoids in the new valve body. Filter + oil done as well. Will put new battery today or tomorrow.

[VinnysS4]

TC

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[JayDog747]

Will have to see what happens when you replace the battery, but you're probably not far from this place:

http://www.levelten.com/

[pauliusmac]

Yeah. Well i got all stuff done by Redline Speed Worx. The level 10 is like 1:20h drive. So with trans which kinda works kinda doesn’t is a lil risky. So i’ll just give up and try to find a used trans around the area..

[pauliusmac]

Replaced battery. Still same issue. Put in reverse, keeping foot on the brakes. I feel it go in reverse, then PRNDS and chevk engine light up. Can feel vibrations.

[ZimbutheMonkey]

Buy a zip kit from sonnax and do it yourself for like $500 with fluid... if it is in fact solinoids in the mechatronic unit (valve body)

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This

It could also be the seal between the valve body and the Mechatronic unit. They often crack and bleed pressure.

Deal with it immediately though.

The lack of pressure will quickly ruin the rest of the transmission.

In fact, if it's been acting up for a while, I'd start hunting for a used trans as you've probably worn the clutch packs or the TC clutch already. No sense in spending $700 for a zip kit and fluid just to repair a half wrecked trans.

[roboto_1337]

seems like good info.

[pauliusmac]

Yep. Thanks everyone. I'll take the used trans route. I had thrown too much into this one and it makes no sense anymore to look for "it might solve or might not". Found a couple used trans, just need to get them shipped to the shop and replaced. As zimbu said, i dont want to ruin the TC from mine and most likely the clutch packs are shot already (Level10 opinion).
Anyone knows actual labor time for trans replacement? As of now i get $1200 quote, but level10 said it could and should be done within $1000 + 200$ fluids and trans.
And one more question, any difference if i put the same code trans (GUR) or other code (HHU or HBU)? would that req modifications, flashing etc?

Thank You!

[blitz2190]

Not sure but I would check the output flange support bearing diameter, I had two 5hp19 transmissions, one from a b6 and another from the c5 a6 3.0, ended up swapping most of the front diff because the support bearings are different.

[pauliusmac]

Yeah but you were swapping from A6 to A4. both GUR and HHU are S4's B6 6speed's Autos.. Can't find info on the differences though.