C5 Gearbox problem

[RS6Rottweiler]

Hello all;

Looking for some advise or if anyone else has had the same problems I am experiencing with my C5 Gearbox? My car has been chipped and produces approximately 507bhp and as far as I am aware chipping also remapped the gearbox?

I started to experience problems about a year ago when I first start the car in the morning, when I select drive the car hardly moves similar to a slipping clutch, if I stop and restart the engine and select drive again everything is fine. I have no problems with reverse and usually the problem does not show its self again that day. However of late the problem is very intermittent, somedays I have no issues and other days it happens quite a lot. I also noticed last summer with all the good weather that we had that it never happened until the colder wet weather came back? As far as I am aware I am not experiencing any issues with hunting, gear change or anything else like that so I wondered if anyone else has experienced this problem and what was it diagnosed as and how was it repaired?

Star Performance look after my car and they think it could be a solenoid problem which I believe requires the removal of the gearbox to access the solenoids and they have told me that the only place in Scotland that does this is Mackies in Glasgow. Has anyone used Mackies and how did you find them?

Thanks in advance for any advise you can give me.

[Shoppinit]

Probably fluid level / quality. Time for a gearbox service.

Also if you go to drive too soon after starting you can run into problems.

I've never heard of a solenoid failing. Sounds like grasping at straws to me. And the box doesn't need to be dropped to get at them. That's bollox.

Might be a valve body problem.

First scan your car for codes.

[RS6Rottweiler]

Hi;

Thanks for responding, the gearbox was serviced about two years ago oil and filters changed so this could get rechecked and see if it makes a difference? I wasn't sure where the solenoids are hence why I have come onto here to get advice from more knowledgeable guys> I have to admit that it did appear strange that solenoids would be put inside a gearbox, they did clean up all the electrical contacts but this made no difference?

Not sure what you mean by valve body problem could you elaborate on this for me?

The main reason for trying to find out what is wrong is so that I can hopefully get an idea on whats wrong with the gearbox before I give a blank cheque to Mackie's or who ever will be carrying out the repair. It could be nothing or it could be something serious but apart from not going into drive when selected it appears okay, however, this fault resets if I start and stop the engine. I have noticed recently that it does jump into gear when this happens and when reset it doesn't, there doesn't appear to be any other issues that I have noticed, all other gear changes are smooth when driving slow or pushing the car hard?? Hoping I can get to the bottom of whats wrong as it would be good to get it resolved and hopefully it won't be too expensive, but I'm not holding my breath on that one?

[grizz]

Do a diagnostic as it could just be the gearbox switch on the side of the box .

[RS6Rottweiler]

Thanks Grizz;

I will get Star performance to have another look and see what failure codes come up and mention what has been said, thanks for your help.

[iaingbrown]

I had recon. gearbox installed by Mackies about five years ago. No problems with them. Not cheap, I think circa £6k plus the old box.
The car was transformed: probably drove 10-15K with box on the way out. I've had one gearbox service from them since ( about £200?) not sure what they do apart from change the ATF tho'.

[bilko1]

Probably fluid level / quality. Time for a gearbox service.

Also if you go to drive too soon after starting you can run into problems.

What problems are you talking about Shop? I've never had a problem yet but perhaps I'm too slow.

[gingertoss]

Mackies service mine. Circa £300 for a fluid and filter change. They did say mine was a doddle as there are no cats in the way.

[RS6Rottweiler]

Hi, apologies for the long delay in getting the fault code information but got there in the end. I am told there is one gearbox fault code that has come up so would greatly appreciate any information / advise anyone can give me on the possible fault and solution to this problem?

Fault Code: 18243 Pressure Control Valve 5. P1835-35-10 Short to Plus Intermittent.

Anyone got any ideas what is causing this and what the solution is?

[mik15]

i'd start by checking the TCU, some water might have got inside, check all the pins for corrosion, clean them and then put it back together, clear the code and see what happens...next would test the solenoids with the VCDS and see if all act as they should....

[Shoppinit]

Sounds like changing that valve might be the place to start.

[longman h]

Right, after doing some research, I think you're going to need to replace the wiring harness that holds all the solenoids/valves to the mechatronics unit.
Funnily enough I've just ordered one of these to get rid of the transmission fluid temp sensor error I'm getting.
This is what the harness looks like once it's removed;


I'll try and find out the Audi part number and post it up.

Just for some info, this is a photo of the wiring harness in situ. The lead going to the top of the image is the temp sensor.


Hope this helps.

One thing I'm contemplating about doing is driving over to Dortmund and having the mechatronics unit completely refurbished by ZF themselves. It's quite cheap and from what I've read on other forums, it's solved all their trans' issues.
Have a read: http://www.bimmerboard.com/forums/posts/527361

[longman h]

Ps. It may be slightly more expensive for us RS6 owners as they'll probably need to remove the engine first!!!!

[mik15]

if they're only doing the VB no need for engine removal...very interesting article and that BMW is also running a 5hp24...for cca350Eur is really cheap compared to what results you get...look for automatic GB parts here too: https://www.automaticchoice.com/

[el_ringo]

Wouldnt a new valve body do the same as that service?