[Boland01]

Our 2007 335i with 94K miles on it has randomly just started to shift poorly, slip etc,.. The next time it drives just fine. I pulled the codes and am getting a 4F8A (4-5 ratio monitoring code).

I reset the code and now 20 miles later it has come back again. Anyone have any experience on what the root cause could be?

I'm hoping it might be the mechtronic sleeve, sealing sleeve that goes above the solenoid valve body or the transmission solenoids.

So far an internet search hasn't turned up anything definite. Any help is appreciated.

[mweisdorfer]

Originally Posted by Boland01

Our 2007 335i with 94K miles on it has randomly just started to shift poorly, slip etc,.. The next time it drives just fine. I pulled the codes and am getting a 4F8A (4-5 ratio monitoring code).

I reset the code and now 20 miles later it has come back again. Anyone have any experience on what the root cause could be?

I'm hoping it might be the mechtronic sleeve, sealing sleeve that goes above the solenoid valve body or the transmission solenoids.

So far an internet search hasn't turned up anything definite. Any help is appreciated.

It's probably a good guess.

I'd buy the other 4 rubber sleeves while your are at it.. I'd also do a tranny flush through the transmission cooler line. You will need a special tool to get the return line off, but it's only $13.00 or so on Amazon.

Most folks would probably tell you to replace the solenoids too, as a faulty one or two could also cause this problem.

I'd get :

Solenoids -

https://www.fcpeuro.com/products/bmw...SABEgIlpvD_BwE

Megatronic sleeve sealing kit -

https://www.ebay.com/itm/For-BMW-04-...YAAOSwFNZW1XIr

Just use the part numbers listed above to order on FCP euro.

You'll need 14 qts of synthetic ATF, which is BMW approved, & the pan filter.

To flush the tranny, all you do is take the return line off the AT cooler and have someone turn on the engine. Drain the ATF from the return line into a marked (mark it by the QT) container. Once you get 3 qts out, stop the motor & fill up the pan with 3 qts. Repeat until you have bright red fluid coming out the return line. The return line will be the hot or warm line. This is the only way to get 99% of the tranny fluid out of the tranny & torque converter. Otherwise, you are only replacing maybe 70% of it doing a traditional tranny fluid & filter change.

[Boland01]

Thanks. I just ordered all of the above parts from Pelican Parts. They had the best deal on the solenoids. I also, drained the fluid as the car is not going anywhere until I get it fixed. No metal or pieces of clutch in the old tranny oil.

Got my hopes up now it's not mechanical.

[Boland01]

Originally Posted by Boland01

Thanks. I just ordered all of the above parts from Pelican Parts. They had the best deal on the solenoids. I also, drained the fluid as the car is not going anywhere until I get it fixed. No metal or pieces of clutch in the old tranny oil.

Got my hopes up now it's not mechanical.

Ended up replacing the solenoids, the four seal to transmission housing, seal for the valve bodyto pump and mechtronic sleeve. Also, used a new ZF pan. The seal for the valve body to the pump actually was in pieces when I took it off so that was most likely the root cause.

I reset all the adaptions and erased the 4F8A code and then drove the car for ten miles. Upshifts 1-6 are all great . The 3-2 and 2-1 downshifts are more abrupt but I think that is the transmission adjusting to the reset and new solenoid valves.

Later this week I'll take it on a longer drive a try and run it through the ZF relearn cycle. For now, it looks like the problem is solved.

[Boland01]

Update: 100 miles later no issues. Shifting great too.

[leif20]

Instead of starting my own thread i'm going to bump and piggyback this one.


2006 BMW 330i with 131k miles
ZF6HP19
Around 120k miles: Pan+filter swap, fluid change with zf lifeguard 6, adaptations reset

Car has been driving wonderfully since trans work 10k miles/10 months ago. I drive it like a grandma in the city, but very hard on the highway. Most highway trips will see a pull from 3k-6k rpm in 4th gear a few times, so lots of downshifting in to 4 and 4-5 upshifts at high power. After driving 120 miles for a road trip this past weekend on the way home I had an odd 4-5 upshift (delayed shift, rpm flare). I tried it twice more, and after the third mis-shift the trans entered failsafe limp mode. Restarting the car removed the failsafe mode, and the car shifted fine for the most part except for a couple of missed shifts again from 4-5 on power. Limp mode was not re-entered for the duration of my trip, and I haven’t seen it since.

When I got home I pulled the code 4F8A 4-5 ratio monitoring.

The symptom is after 3.5k rpm the upshift command is sent, and I can feel the attempted shift (jolt in driveline), but 5th gear is not engaged. Backing out of the pedal (ie. Less power demand) triggers the shift, but it seems as if there is not enough hydraulic pressure to engage 4th. All other upshifts, and all other downshifts are fine (so far).

Given the above and based on other research on this and other BMW forums my plan is to do the following:
1. Check fluid level, top up if necessary (can do this weekend). I don’t expect this will entirely solve the issue as low fluid level would probably show up in other shifts as well, but it’s worth a shot.
2. Replace seals to valvebody (need to buy parts). I think (and hope) this is the issue. I have read a thread or two where replacing the worn seals has dealt with this issue. Is it likely that it’s only the bridge and valvebody seals, or is it the solenoids?
3. Inspect solenoids, replace if necessary (buy solenoids). Is there any way to clean the solenoids? From what I understand I can test them for resistance, would this indicate whether they are faulty? Or should I just pop new solenoids in and call it a day?

If it is a hydraulic issue, why would it be limited to just 4-5 upshift?
According Sonnex ZF6HP19 valvebody and mechatronic service doc: https://s3.amazonaws.com/sonnax-dev/...AutoChoice.pdf
For driveability concerns specifically the 4-5 upshift flare, they recommend a "valvebody hydraulic service." Is that the full seal+solenoid replacement? What else can be serviced?

Any feedback is appreciated. Hoping to keep this car for at least a few more years, and I’d like to keep driving it moderately hard as well. If I can’t do WOT pulls anymore that’s fine, but I’m seeing a bit of slip at even 50% throttle at mid rpm in 4th and I’m not too keen on that.

[Boland01]

On our 2007 335i with 94K miles we had the exact same 4F8A code. The car would shift erratically, randomly and even go into neutral. When you turned it off and restarted it was fine- For a bit.
It turns out on our tranny the double adapter seal had torn. It's located above the valve body. Bad news is you have to drop the tranny pan and remove the solenoid valve body to get to it. I ended up replacing the solenoids (probably was unnecessary), the three single adapter seals, double adapter seal and mechatronics since I had it all apart already.

Since then the tranny shifts like new. Remember to reset the tranny adaptations if you replace the valve solenoids. Good luck.

[leif20]

Originally Posted by Boland01

It turns out on our tranny the double adapter seal had torn. It's located above the valve body. Bad news is you have to drop the tranny pan and remove the solenoid valve body to get to it. I ended up replacing the solenoids (probably was unnecessary), the three single adapter seals, double adapter seal and mechatronics since I had it all apart already.

This is ultimately my question - do I replace the solenoids too since i'll have the trans apart already (at additional cost of $350 or so), or save that $350, replace the seals, and see how that goes for me.

Time to jack up the car, take all this apart and put back together, and do the adaptation reset is probably 4 hours. So I guess It makes sense to replace the solenoids to only have to do this job once!

[Boland01]

I guess it depends if you want to have to go back into the transmission and remove and do everything again if it's not the adapter seal. The good thing is my adapter seal was literally in two pieces so it was easy to see once I got to it. For me it was just easier to get it all done at once. Check out Pelican Parts on the solenoids. I only paid $214.24 for them. That was early January this year. The total bill for everything including a new transmission pan was $390.06.

[leif20]

I emailed Sonnax transmission support, and a local but highly recommended transmission shop.

My symptom is good shifting but RPM flare on 4-5.

Sonnax said it is likely a worn bushing in the stator of the pump leading to excess clearance and leaking of oil pressure, preventing good E-Clutch engagement.

The local trans shop thinks it's actually worn clutch packs on the E stack, but also mentioned the Stator bushing and potentially a pressure relief valve in the pump.

Most issues with these transmissions I have seen here online are solved with the solenoids, seals, new fluid and resetting adaptations. I'm wondering why my transmission would have the worn clutch packs or bushing when there are plenty success stories with the solenoids.

[turbohugh]

Originally Posted by leif20

I emailed Sonnax transmission support, and a local but highly recommended transmission shop.

My symptom is good shifting but RPM flare on 4-5.

Sonnax said it is likely a worn bushing in the stator of the pump leading to excess clearance and leaking of oil pressure, preventing good E-Clutch engagement.

The local trans shop thinks it's actually worn clutch packs on the E stack, but also mentioned the Stator bushing and potentially a pressure relief valve in the pump.

Most issues with these transmissions I have seen here online are solved with the solenoids, seals, new fluid and resetting adaptations. I'm wondering why my transmission would have the worn clutch packs or bushing when there are plenty success stories with the solenoids.

Sonnax is correct. E-Clutch relies on the stator pump bushing. I believe some of the early Zf6HP21's had a defect with that bushing. Once it wears the E-Pack doesn't stay clamped. Then the pack wears and you start getting E-Ratio errors.

Only real corrective action is replace the bushing and replace the clutches.

[leif20]

Originally Posted by turbohugh

Sonnax is correct. E-Clutch relies on the stator pump bushing. I believe some of the early Zf6HP21's had a defect with that bushing. Once it wears the E-Pack doesn't stay clamped. Then the pack wears and you start getting E-Ratio errors.

Only real corrective action is replace the bushing and replace the clutches.

In the comments of the video below they say a similar thing.

" typically the bushings inside the transmission wear out due to low oil pressure from valve body. "

I will drop the pan and have a look at these pathways. If my E-Clutch passageway is 'leaking' air, I guess that means my E-Clutch is shot. This is super annoying. I was already in the transmission last year to replace pan/filter/fluid. Had I known that the bridge seal goes bad and leaks oil pressure I would have replaced it! Not such a difficult job to do. Way better than a whole new transmission.

I did tons of research before buying and while owning this car. I never came across any suggestions to replace these seals as preventative maintenance, only if you were having shifting problems. Well Now I have a shifting problem, and TBD whether this will fix it. I think it was my driving style that led to this premature wear, I'm sure if I had driven the car less hard (less high RPM pulls in 4th gear) I would have gotten more time out of this trans. Every other part of the car was running so well though, it was hard not to push the car.

This weekend my plan is to get under and test these pathways. If it's not leaking too bad then replace the bridge and other valve body seals now as my first action. Reset adapts and then drive the car like a grandma until the car won't upshift anymore. Then???

[leif20]

My Bridge seal was in decent shape, not torn but the edges were fairly bowed in. I still think it was probably holding pressure despite this. The finger seals were also in decent shape but quite hard. I didn't replace the solenoids because I wasn't having any shifting issues other than this 4-5 slip, if it gets worse then I'll look at the solenoids. I reused my old fluid which was much darker than I would have preferred, I assume from the clutch slipping that has occurred. Since refilling and resetting the adaptations I havent had an issue, but I also won't be driving the car hard anymore to avoid future problems. The trans shifts very smooth from 1-4, there is a slight bump going in to 5 and a noticeable bump going in to 6th. I have to think this is because of the e-clutch hydraulic circuit not being fully intact anymore. I'm not going to have the trans rebuilt so I'm just going to leave this.

I managed to get the car back together after a heck of a time re-installing. I put it all back together once and attempted to start the car, but it didnt start, and the shifter was jammed! The shifter issue was due to having the shifter rod and the slider on the mechatronic misaligned. The piston on the mechatronic side was jammed against the selector rod, so I was really fortunate that I didn't break it. This required draining and removing the pan and mechatronic to reset.

Secondly, I did not disconnect the battery during this service and when I went to reconnect the mechatronic connector I didn't twist it to the full lock position. I had a lost communication fault with the transmission. Diagnosing using the ZF guide led me to test for voltage at the power supply pins of the connector, and I was missing voltage at pin 14 which is the ignition power for the trans. I had a blown fuse, F01 in my 330i, so that was my issue there.

Thirdly in all my troubleshooting I still couldnt get the car to start after this fuse re-insertion, so I had to disconnect the battery and charge it up. I think letting the car lose all power and then giving it a full charge really helped, after clearing codes on the DME the car finally started.

[leif20]

Sonnax tech manual claims the middle one is the e-clutch.


Alright, so I got under the car and was able to have a look at these passageways. One thing I've realized is that these two videos claim opposite things! In the first video (the supposed failure) he pressurizes the port closest to the pump and a "whoosh" is heard. Supposedly this means the e-clutch bushing is shot.

In the second video the guy rebuilding the transmission says that in order to check the integrity of each clutch pack you can pressurize the packs. He pressurizes the one closest to the pump and says that's the 1-2-3-4 clutch (a-clutch). It makes the same dull whoosh as the other video. He then pressurizes the outer one and says that's the e-clutch!

I did this on my car, and I had the air whoosh on the inner one, and the pressure holding on the outer one. So is the clutch shot or not? How could a trans rebuilder show this video and claim the trans is good to go?

My Trans:

"Bad" Bushing:

"Good" Bushing, rebuilt trans:

I emailed ZF, Here is a transcript of my conversation:

Me: Does the pressure check sound bad?

ZF: The E clutch always has a little bit of a leaky sound compared to the A clutch, because of the way it is sealed. The only way to tell if it is damaged is if the fluid was burnt or if you actually inspect it. If the fluid is burnt, based on the code you have I'd say E would be burnt. The pressure check doesn't sound bad. I do not think you have any serious leakage in the clutch. However, the 4F85 code could mean the clutch is burnt. If the vehicle is going into fail safe, and it has been driven in that condition, then the clutch is probably burnt. I would suggest going through the components and replacing worn items including the bushings and pressure regulators.

Me: Actually I have code 4f8A

ZF: The internal shaft and drum bushings should be replaced. The code usually signifies clutch E is burned. Especially if the vehicle was going into fail safe. If the transmission fluid is clean and full, then the issue could be a simple solenoid replacement. If the fluid level was low or burned, then the E clutch is more than likely burned.

Me: How can I tell if the fluid is burned?

zf: Typically, the fluid would smell burnt. I do not know of a test other than lab work. If the fluid is caramel-light brown in color, but it doesn't smell burnt, it is probably alright.


So my fluid was dark brown but did not smell burnt. 10k miles ago I did a fluid and filter change but not flush. The fluid i pulled out a year ago was very dark and dirty, so I imagine that's why I have darker fluid in there now (mixed with the stuff I didnt get out). So according to ZF, if my fluid is in OK shape (clutch hasn't been burnt yet) I should be good to replace the solenoids and try again. With my pressure test i'm sure that there is some leakage at the bushing, but perhaps solenoids will help the shift complete faster and minimize the effect of this.

[leif20]

Updates on my situation:

I also pulled a different code, 4f86 for the 4 to 5 gear change, at 3800 rpm. This was AFTER completing the bridge and 4 finger seal replacement. Shifting from 4-5 at around 4k rpm is pretty common experience (residency, in automotive terms), so I was anxious to solve this issue. I read enough on this site, other sites, and through some PM's to convince me the solenoids were worth a shot ($300 fix vs. something an order of magnitude greater). I ordered the solenoids and committed to doing this job a 3rd time.

200 miles after the solenoid replacement my shifts are just as good as ever. I havent yet looked at the hydraulic pathways to evaluate which solenoids were bad but my shifting is great so far (knock on wood). I don't plan to drive the car as hard as I used to, to prolong it's life. I'm hoping to take this car to 300k km.

If you are getting trans faults and you have a high mileage trans you will probably benefit from this service. If I had a lift I wouldnt have balked at doing this service, but having the jack the car up level on jack stands is a pain in the a$$ and made me hesitant to do the job.

If you buy a high mileage e90 with a ZF auto, at the first sign of trans issues I would recommend this. I know it's a bit much for a 'preventative' maintenance item, but given how much information there is out there on failure cases for the solenoids to me it seems an easy decision. In hindsight I should have replaced the solenoids last month when I pulled the bridge seals and saw that it was in good shape. The pressure testing of the circuit led me to think it was 'blown' but according to ZF some leakage is normal.

If anyone has any questions feel free to post or PM me.

[Boosted_Bavarian]

Originally Posted by Boland01

Update: 100 miles later no issues. Shifting great too.

Any Updates almost a 2 years later? Im getting E clutch fault aswell & not sure if i should do full trans service or just save it for a new trans with lower miles. funny cause im at 93k miles. Iv been told Seals & Solenoids will fix it. iv also been told the bushing is already bad 🤷

[Saif2018]

Originally Posted by Boosted_Bavarian

Any Updates almost a 2 years later? Im getting E clutch fault aswell & not sure if i should do full trans service or just save it for a new trans with lower miles. funny cause im at 93k miles. Iv been told Seals & Solenoids will fix it. iv also been told the bushing is already bad 🤷

Full transmission service (pan, seals and Solenoids etc) highly recommended. More often then not they fix a lot of issues.

For those suffering from clutch slip, especially on 4th gear, if you have XHP, you can activate line pressure bump to increase clamping pressure to see if it helps. Can also increase torque reduction to reduce load on clutches during up shifts.

[leif20]

What you can do is the following:
When Cold
- Do some more aggressive pulls (2-5) in D mode and in S mode, see how car behaves
- switch to manual and do the same, pull from 2-5 and then back down (switch around 4k rpm, downshift in mid rpm as well
- in gear 3/4/5, in manual, accelerate from 2.5k to 5.5k rpm, and see if the car pulls or slips
When hot
- repeat above tests

Then you will have an idea of what the issue is. It is important to identify if you have slipping in gears, or between shifts. Be careful not to have the transmission slip too much, or if you do find a problem area, don't repeat that scenario too much (can cause transmission damage).

I have to agree with Saif, based on my experience. It has been 1.5y since changing solenoids and the car runs good as new, WOT shifts 4-5 included (although I do this MUCH less now). Manual shifting with the lever is still great too. All new seals along with the solenoids (*** and transmission adaptive value reset ***) fixes many issues with these transmissions and can be considered a refresh. Let us know how it goes.

[iqraceworks]

Just a side note....the solenoids don't just open and close like a valve, they modulate......so they are supposed to also control how much pressure goes to your clutch packs.

When my 6HP21 started to slip in 5th gear (e-clutch pack), I redid all of the seals, filter pan, and fluid....but still had the slipping issue in 5th. Next I replaced all of the shift solenoids.....problem solved.

When I did some more research to find out WHY new solenoids fixed the sliping issue, it sounds like as they wear or start to go bad....they might not modulate correctly, and don't provide the correct amount of pressure to the clutch packs....causing them to slip.

Even after jumping up to an E40 tune that makes a bunch more torque, no more transmission issues (knock on wood).

Long story short....while you are in there, replace the solenoids.

As far as parts....I used Eriksson Industries. Best prices around, and they specialize in ZF transmissions so they are good about technical help and questions.

[StiffUpperLens]

Great thread, wholey worthy of resurrection... so it shall be done.

So i experienced this last week. Hard drive through the mountains in my E90 330d LCI. Manual mode, changing around 4,500rpm and as with above, 4-5 delayed shift, rpm flare. Did this 3 more times and then thew the 004F8A error with limp home mode.

I have XHP installed, and it was my first drive after updating to v4 of the software. So ,my first though was it may be something to do with XHP, or maybe my settings where too aggressive. So I went home and reinstalled it with less aggressive settings, and bumped the line pressure. Sadly the problem remained, but it didn't throw any more errors.

Coincidentally, I had already ordered a service kit the week before this happened. It was due for new fluid, I ordered a new pan and all the megatronic seals too. The shifts have never been bad so I felt the solenoids could wait.

Anyway, I serviced the trans yesterday, the seals definitely were due, they were flattened and hard. The oil was light brown, darker than new (80,000kms worth) and not burnt.

Today I took her back out for a brisk run in the hills and the car shifts perfectly in all modes and under full power. Until the trans temp hit 93deg c and.... it happened again.

Under that temp, it's as sound as a pound. Under normal driving conditions in nanna mode, it is perfect like a kitten purring after a nibble of catnip. Go over that temp and drive it aggressively, it comes back.

To be fair, my car has 218,000km so I can't blame it for needing a part replaced here or there. It's just otherwise in pristine condition and feels like new. So this is a bit of a blow and reminds me she is 13 years old after all and maybe I should plant my feet back on the ground and suck it up.

If this thread is anything to go by, I guess it's time for solenoids and to do the bloody job again. What a c*nt of a job it is too. With the 330d, you have to drop the back of the trans to get access to the megatronics connector. So gearbox mount bracket, exhaust mounts all have to go, adding to an already shitty job if all you have is jack stands.

If anyone else stumbles across this and has any other suggestions, I'm all ears

[deepblonde]

Originally Posted by Boland01

Ended up replacing the solenoids, the four seal to transmission housing, seal for the valve bodyto pump and mechtronic sleeve. Also, used a new ZF pan. The seal for the valve body to the pump actually was in pieces when I took it off so that was most likely the root cause.
it looks like the problem is solved.

Where is the seal for the valve body to pump?
How do you access that?
Still going well?

[ulissestoga]

My 135i N54 ZF 6hp21 transmission had error 4F84 (Gear Ratio Monitoring Shift 3-4). Always when changing from 3rd to 4th the transmission went into emergency and locked in 3rd gear.
The oil, filter, seals, clutches and valve body with solenoids were changed. I bought a new TCU, but it was defective, so today I use the car's original TCU.

Now the car changes all gears normally if it goes slowly, but if it requires a little, the transmission goes into emergency, most of the time showing only the error 4F8A (Gear Ratio Monitoring Shift 4-5), and sometimes only the error 4F85 (Gear Ratio Monitoring Clutch E), these errors never appear together.

I've studied a lot about this exchange rate, but I still need help.

What hypotheses do I suspect are causing the problem:
- Low oil level (I don't know if the mechanic completed it according to the ZF/BMW manual)
- A problem with a solenoid
- TCU with problem

Any idea?