Clutches C and D not plausible

[jelico1]

Hello everyone,

Recently I started getting jerking when the car was changing gears and a recent drive train malfunction error but after a start/stop the error went away but the car still jerks and sometimes cuts power.

I brought the car for a diagnostic and the tester read
:Code: 4204C1 - "Gear-ratio monitoring: Clutches C and D not plausible"

Does anyone have experience what this could be what repair costs would be involved?

Car: BMW x5 F15 40D
Miles: 143.000KM

[SunjaKim]

Welcome.

I expect your only option with that code and symptoms is to replace the transmission.

Has the fluid and filter been changed? - not that it will resolve the problem, but good info for others.

The below is German - your browser should be able to translate:
https://www.f10-forum.de/forum/threa...alyse-was-tun/

[jelico1]

Yes the fluid has just been changed recently when the jerking has started as some mechanics said that it would fix it but it's just getting worse

[SunjaKim]

Originally Posted by jelico1

Yes the fluid has just been changed recently when the jerking has started as some mechanics said that it would fix it but it's just getting worse

I meant was the fluid and filter done at the recommended mileage interval - definitely not a cure for problems, but a preventative measure.

[m4forum]

This is most likely related to the mecatronics which controls the transmission. Unless driving in limp mode which expose clutches to high wear replacing the mecatronics can be an alternative.

Check sonnax as they have solution for it.

Regards

[Chilled]

is the jerking mainly when you are going into 3rd and 4th?

Given the price of a used unit, thorough troubleshooting doesn't make allot of financial sense. If you are ok with $$ of full disassembly and analysis, the labour hours + parts + assembly will roughly = a new unit. So just get a new transmission.

The most you/your mechanic can check is the solenoids and vacuum test the mechatronic block. Granted this test alone will not be cheap as you do need to full oil service on top of the labour hours (approx. 4hrs) to remove, disassemble, clean, test, reassemble, fit, fill oil. This does not include the time + parts needed to fix (if possible) the block.

[jelico1]

I just went to a specialised mechanic he said it's the clutches that need replacement, so I need a new clutch pack
Whole repair coming in a 2600 euro

[SunjaKim]

Originally Posted by jelico1

I just went to a specialised mechanic he said it's the clutches that need replacement, so I need a new clutch pack
Whole repair coming in a 2600 euro

That would go against the advice offered by others in this thread, but not an issue if you get a written guarantee that your transmission will function and perform like a new one after the quoted repair, and if not, what would be the next course of action.

[Chilled]

Originally Posted by jelico1

I just went to a specialised mechanic he said it's the clutches that need replacement, so I need a new clutch pack
Whole repair coming in a 2600 euro

Wow, that cheap. Assuming he is doing all the clutch packs (A-E), orings, bushings, etc and not just the C,D packs.

Since you are already tearing into it, do get him to vacuum check the block and refresh all the wear items, ie. the sonnax zip kit.

[m4forum]

As we have other cases of transmission issues would be interesting to share how the diagnostic was performed so others can use that as reference.

[jelico1]

So he is replacing the C & D packs with new ones, new gaskets and re-conditioning the
torque converter said this is very common in this model of X5

The diagnostic came from the BMW garage they put a tester through

[m4forum]

I understand. if possible would be very helpful for the community to post the results from this repair as well the condition of the used parts to evidence the failure. This way others can benefit from it.

[Chilled]

Originally Posted by jelico1

So he is replacing the C & D packs with new ones, new gaskets and re-conditioning the
torque converter said this is very common in this model of X5

The diagnostic came from the BMW garage they put a tester through

Considering that you need to remove all other clutch packs to get to C & D, kinda does not make sense doing all that work and not replacing them. The clutches them self are very cheap, the labour to remove transmission+ disassemble is not.

Same could be said about the mechatronics valve block. If clutches C & D are gone, given the amount of clutch material that is floating around in the oil. It would be a really good idea to clean out the mechatronics valve block and inspect if any of the valve bores have worn out.

or Maybe they are looking for repeat business.

[m4forum]

is there any type of oil analysis to identify excessive clutch wear?

[m4forum]

Maybe cooper from the disks but I have never done it.
I believe blackstone labs can do transmission oil ... maybe they can provide more details.

[Tomcat_F15_STL]

It is my understanding Oil analysis is frequently inconclusive unless you have a running history or baseline.

If the transmission is failing, no amount of oil analysis is going to make a difference to the outcome other than further lightening your wallet.

[m4forum]

Originally Posted by Tomcat_F15_STL

It is my understanding Oil analysis is frequently inconclusive unless you have a running history or baseline.

If the transmission is failing, no amount of oil analysis is going to make a difference to the outcome other than further lightening your wallet.

not really. for example high levels of sodium or potassium indicates coolant. lead can indicate bearing wear. Certainly wont be 100% diagnostics but certainly can provide a direction. With history even better.
I see value on it

[SunjaKim]

Originally Posted by m4forum

not really. for example high levels of sodium or potassium indicates coolant. lead can indicate bearing wear. Certainly wont be 100% diagnostics but certainly can provide a direction. With history even better.
I see value on it

Would that be applicable for the transmission and engine ? - no potential of coolant intrusion in the transmission as far as I can tell.

[m4forum]

this is what I wrote on my previous post ... I believe cooper is related to clutch plate wear. suggestion is to call blackstone labs and ask them.

[Chilled]

Clutch packs, are just that. Clutches. Just like in a manual car. They wear out. Difference is use and material dictates how quick.

Considering that the drain plug on the F15/F16 is plastic and is in that one time use category. Is it really smart to try and drain out a couple of ml to get a sample? Risk dropping all of oil/ needing to get a new pan and do a full re-fill.

If its not engaging gears, its either a solenoid is gone and/or you toasted a pack (or more serious mechanical). Either way you tearing this thing apart. As Tomcat mentioned, doing an oil analysis whilst you cant engage gears is not going to fix it.
ie. If your rod bearing are toast, will doing a oil analysis fix them? No. So just put the money to the fix.