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C7 OB5 3.0tdi Gearbox

Wudka

New member
Hey everyone,

Has anyone found a reasonable service price for this gearbox?
The oil is listed as sealed for life apparently which is bs and some workshops have initially not wanted to work on it, moving to silly pricing to complete a service.

I’ve found Meyle oil and filter kits which appear to be “reasonably” priced However, mechanics are sceptical of quality.

Big difference in price to the 1k plus just for the OEM oil at less than 1/3.
 
I too would be a bit skeptical on the quality of the Meyle stuff. I assume either Motul (eg Gear 300) or Redline (eg MT90) have oils which match the viscosity of the factory gearbox oils and would personally be much more comfortable using something reputable like this. FWIW I've used the Redline stuff in an RS4 in the past and had good results with it.
 
Well,

It seems that I am up for a much bigger issue, as of today, the car went bezerk.
Every single fault I think it could come up with lit up. Popping out of gear, then back into.
Showing malfunction of the following -
- TIre pressure management, park brake, gearbox, light level, air suspension, atability control....

My brother ran a diagnostic and it identified a lot of errors.

My first question is, does anyone have a diagram for locations of all the computers?
I would like to check all plugs and connections.
 
Have you checked the condition of the vehicle's battery Wudka? On modern cars when you get a myriad of issues occur all at the same time this can often be battery related.
 
Have you checked the condition of the vehicle's battery Wudka? On modern cars when you get a myriad of issues occur all at the same time this can often be battery related.
Hi,

Yes, it was stating on the scan that it was at 60%. We noted that it was showing a voltage below 12V, so I replaced it at substantial cost.
Didnt make it home without all the warnings, limp mode, dropping out of gear.

In other words, same issue back.

Yesterday I checked ove the ECU in the engine window bay, cleaned the ground connection and inspected the harness connections. Other than a slightly corroded ground, all else appeared to be fine, with the relays and fuses looking clean - the fuse/reay box hadnt taken any water.

After an initial drive, all was well, with car at temperature. As I set up to go for a longer drive, problem returned.

It appears that this is temperature related. When engine cold, car runs perfect, for the time being.

I noticed over last few months, in the hottest period of the year, there are moments when the car runs one bar below the set temperature on the display... but momentarily, which I thought to be strange and often in traffic, which makes it more questionable.

I need to get under it and inspect the gearbox wiring harness for corrosion.

Check all that before I even contemplate mechatronic unit issues etc. But I do not understand the magnitude of faults simultanously. And then it runs without fault... until they come back.
 
I had something similar on my S3 on hot days. For me, ended up being the connector to the fuel pump... When it got really hot, we suspect that the connectors 'expanded' and were not making great connections. What I would do is just unplug it/move it around and it would come good for some time. I even swapped out a whole lot of parts, but the problem came back (and would work when cold).
So far, this summer (fingers crossed), the new connectors have fixed the issue.. Maybe something similar with yours..
 
I had something similar on my S3 on hot days. For me, ended up being the connector to the fuel pump... When it got really hot, we suspect that the connectors 'expanded' and were not making great connections. What I would do is just unplug it/move it around and it would come good for some time. I even swapped out a whole lot of parts, but the problem came back (and would work when cold).
So far, this summer (fingers crossed), the new connectors have fixed the issue.. Maybe something similar with yours..
Thanks Jnr Davo,

I'll add this to the list.
Struggling with it at the moment. Yesterday I checked the main ECU, cleaned the earth connection which has slight corrosion but it did not resolve.
When fixed(If I Manage) I think it will be time for a Toyota.
 
Update to All and a warning to all A6(And possibly other model owners as this solenoid valve is used in multiple vehicles)

I wrote this up on another VAG forum and will repost here in the hope if helps someone and prevents people from loosing the TCM and being cheated out of thousands of dollars.

Further update,

The gearbox coolant solenoid valve is very much so the culprit here, with the plug to this valve also corroded and wet. As nominated in other threads with this issue, the coolant escapes this valve, follows the cabling down via the loom to the gearbox control module plug and then corrodes that away to the point of a multi thousand dollar repair if you do not get sufficient intermittent issues and investigate in time - In hindsight, my car had shown signs a few months back, nominating gearbox cooling issues, but the message disappeared almost immediately and I didn't think to investigate the wiring, instead looking into finding a good price to change the gearbox oil.

I have spent the weekend looking into this and am confident that Audi know about with what I have been able to uncover, yet they choose to do nothing about it.

I would strongly urge all A6 owners to at least investigate the condition of their solenoid valves and check the gearbox control module plug for signs of moisture. If none, then modify the harness to allow water to drip away(Cut the heat sleeves) and cut a drain hole into the bottom of the gearbox control module plug cover.

This might save you thousands in repairs and could potentially save you from a major accident, for if it fails immediately like mine did, then you might get Tboned etc.

Thank you for helping me!
 

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bummer of a problem, but thanks for the warning to all..

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