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Discussion Starter · #1 ·
Hi all,

Here is my experience and most recent episode with the MP4:

I did a small acceleration and suddenly clutch over temp symbol appeared for the first time followed by a transmission fault error. I took it home (have a 4 post ) and checked the fluid levels first for the clutch. It was missing a large amount and inspected the transmission fluid and it was completely full with about 6 quarts over the fill hole (no exaggeration). Indeed, the clutch fluid is in the tranny! :/ How is the clutch fluid getting into trans?

After the error message and before knowing the issue on the way home gear engagement was difficult and gears would slip to neutral and only engage from 2nd to 4th. I think the tranny is toast. Has anyone ever opened up the cover to verify this type of issue? Is it worth opening up the trans to a particular section of the trans where this spillover can occur such as loose bolts separating sections?

Btw, the above happened after twice servicing both the trans and clutch (including new filters).
 

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Im not 100% sure about mclaren transmissions, but this does sound like a classic dual clutch control issue when you have a failing solenoid or two.

Well i hope it is this, because it isnt a terminal transmission issue, you just replace the bad part, if possible or the entire control module like this:
Gearbox solenoid actuator valve block

I've had this happen on a few supercars, similar stuff with overheat warnings, only 1st, 3rd and 5th gear available etc, so fingers crossed for you bro!

On one transmission the cause was debris scoring the coating on the solenoid piston which meant it became stuck in its housing, another issue was contaminants in the gearbox oil clogging up the tiny film-way between the solenoid piston and outer.
 

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Discussion Starter · #3 ·
Thanks for the advice and link.

If it is this, I presume that to do the fix, I need to drop the gearbox entirely, right? Depending on the difficulty of the job, I'll either do it myself or give it over to my trusted mechanic.

My only other fear is that the transmission running the clutch fluid for a while did some other damage to it.

Would a failing solenoid actuator valve block also cause fluids from the clutch to somehow transfer to the transmission?

In fact, in one of my previous trans / clutch service intervals, I noticed that the trans fluid was over the fill hole by about a quart or 2 but only after driving it for a few months. I found it odd at the time that nobody reported this type of issue on the forum, but I didn't make anything of it at the time.

Based on your experience with this type of clutch, what if I fill the clutch again and all runs ok? Would this still point towards a solenoid actuator valve block?

I picked up these codes from the transmission reading from the M-engineering suite:
P123B - line pressure high
P1304 - cooling pressure fault
P2765 - input 2 speed no signal and input 2 speed over range

Thanks again for your support!
 

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I had same issue but the ( code P0701) same over heating message... car go only in1st 3rd 5th and 7th and no R
extended warranty paid for new transmission , per McLaren dealer was CLUTCH CUT-OFF VALVE defectives
not sure if it was reparable. warranty companies choose this route per dealer
 

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Discussion Starter · #5 ·
I had same issue but the ( code P0701) same over heating message... car go only in1st 3rd 5th and 7th and no R
extended warranty paid for new transmission , per McLaren dealer was CLUTCH CUT-OFF VALVE defectives
not sure if it was reparable. warranty companies choose this route per dealer
Thanks. did the Mclaren dealer or mechanic say anything about the clutch fluid making its way to the transmission fluid? The overheating clutch was a result of no fluid left. This is the major issue and I am not reading anywhere this is a common issue.

I filled the clutch fluid again with about 6 quarts to test and in my drive way, Reverse gear worked again as usual. I even brought the engine / trans to normal temperatures and then I again checked my transmission fluid and it did not fill up with clutch fluid. I presume it happens when actually driving and possibly in certain gears - no clue. I'm now hunting a used gearbox and then get the one currently in mine repaired and then sell the gearbox.
 

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I asked them ..It’s not common issue at all they never Seen similar issue .. busy dealer in north California..
Clutch filter /fluid was replaced 3 months prior
Due to main engine seal replacement ..
 

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Discussion Starter · #7 ·
A brief update: I am considering purchasing a used 650 gearbox from the UK - less expensive than a rebuild. I have the earlier MP4. Does anyone know if the 650 gearbox can easily be adapted to the 2012 MP4? I understand that the earlier mp4 version only came with 2 breathers and the newer mp4 and 650 have 4 in total. Anyone know if its possible to run this gearbox with the additional breathers?
 
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A brief update: I am considering purchasing a used 650 gearbox from the UK - less expensive than a rebuild. I have the earlier MP4. Does anyone know if the 650 gearbox can easily be adapted to the 2012 MP4? I understand that the earlier mp4 version only came with 2 breathers and the newer mp4 and 650 have 4 in total. Anyone know if its possible to run this gearbox with the additional breathers?
You can swap it seemlessly.
 

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A brief update: I am considering purchasing a used 650 gearbox from the UK - less expensive than a rebuild. I have the earlier MP4. Does anyone know if the 650 gearbox can easily be adapted to the 2012 MP4? I understand that the earlier mp4 version only came with 2 breathers and the newer mp4 and 650 have 4 in total. Anyone know if its possible to run this gearbox with the additional breathers?
The 12C, 650S, and 675LT all have the exact same gearbox and are interchangeable. :cool:


Kevin P
Supercar Garage - The McLaren Specialist
770-284-0172
Kennesaw GA
* Home of the flying McMedics... The only mobile McLaren Specialist! -We come to you!
 

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Discussion Starter · #10 ·
The 12C, 650S, and 675LT all have the exact same gearbox and are interchangeable. :cool:


Kevin P
Supercar Garage - The McLaren Specialist
770-284-0172
Kennesaw GA
* Home of the flying McMedics... The only mobile McLaren Specialist! -We come to you!
Good to know - much appreciated.

As a side question, do you think by replacing the entire solenoid actuator valve block has something to do with the clutch fluid making its way into the transmission? I've reached out to a few local gearbox specialists about this issue and none provide a clear answer. Although the entire valve block costs around 5k brand new, I wish it was since it appears would be an easier fix that would not require dropping the gearbox.
 

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Good to know - much appreciated.

As a side question, do you think by replacing the entire solenoid actuator valve block has something to do with the clutch fluid making its way into the transmission?
Tire Motor vehicle Automotive tire Tread Wheel


The Green dotted line above represents where the Clutch Fluid (Left side) is separated from the Transmission Fluid (right side). This is where you have an internal seal leaking allowing the two fluids to mix.

The red dots indicate where the valve body (red arrows) attaches to the transmission. Unfortunately the valve body gasket is not your issue, meaning you need to replace the transmission.

At Supercar Garage we swap the Valve Body with the transmission in the car. This is usually the solution if the car is not shifting properly (meaning you cannot access one or two of your gears)

Your issue is clearly a bad seal inside the transmission which is not serviceable without a full transmission tear down and rebuild, so we would just recommend replacing the transmission with a known good unit.

Kevin P
Supercar Garage - The McLaren Specialist
770-284-0172
Kennesaw GA
* Home of the flying McMedics... The only mobile McLaren Specialist! -We come to you!
 

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My only other fear is that th
To me it sounds like you are jumping the gun, are you sure the fluids are mixing? I would dump all fluid out of the box and go again and see.

Thorney Motorsport in the UK can rebuild the box for you as well. Isnt cheap though and probably cheaper to buy a used box.
 

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Discussion Starter · #14 ·
Thanks. I truly wish I was jumping the gun!! However, all signs point towards the mixing of fluids. If all of sudden the gearbox is overfilled by 6 liters to the fill hole and the clutch fluid only drains out approx 2 liters. This happened twice before. It's just that on the previous occasion all the clutch fluid was gone which is why none of the gears engaged.

In my opinion, it can only be the clutch fluid going in there. There are no external leaks and the geabox fluid looks like the clutch fluid when this happens. Also, a strange one on mine is that both the gearbox and clutch weep holes are plugged up.

I recently tested and emptied out the gearbox and remaining clutch fluid and refilled it again. I am now able to go in reverse and seems to work as before, but I know the clutch fluid will again make its way into the gearbox. I presume it's happening under heavy load.

If I was local in the UK, Thorney would be the way to go. Transport costs from Switzerland to UK and return costs just as much as the gearbox. :/
 

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okay well you sound like you know what you are doing and Im sorry to hear this. There are plenty of boxes on ebay tho, also, hate hearing things like this. Thankfully its rare. You can also install a 650 box
 

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Discussion Starter · #16 ·
yes, appears to be rare. I couldn't find anyone on this forum with this same issue, or at least they probably never knew they did. Many claim to lose the reverse, 2nd and 4th. This I had and others probably don't even know why.
I have a 4 post hoist in my garage so easy to monitor.
I also purchased a used 650 gearbox from the UK a few weeks back - has few miles on it. Also, I took your advice about the upgraded clutch used on the 570s / gt (with matching bolts) without the springs showing. While the gearbox is out, best time to do this preventive maintenance.
 

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Okay cool well let us know how it goes. Yes the DLD, change it. The P11 units are shit. Although the later design is heavier by 2kg
 

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Discussion Starter · #18 ·
Thanks.

Mechanic does the gearbox / clutch job when returns from holidays in early August.

Since a used 650 gearbox is being used to replace mine, any other small parts required? I purchased the following so far:
11G0165CPSeal - Input Shaft – Transmission x 1
11G0197CPDriveshaft Snap Ring x 2
00RB038Clip - 16-25mm x 2
11L0263CPO-ring - Coolant Pipe – Tranmission x 3
 

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Sorry I was late to this party. I posted a while back that when I lost the gears and reverse, replacing my SAV solved the issue. I documented the entire thing.

That said, I did have the same codes as you. The other day I had a clutch overheat message. I intend to check fluids today.
 
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