[leif20]

Edit - Problem seems to have been solved by replacing solenoids, and I'm keeping the car. I don't doubt there's been some wear on the trans internals but with the new solenoids (zf replacement from pelican) the car is doing pretty well and I am satisfied.
...................

Hi All, Just looking for some advice here.

My car started slipping between 4-5th gear, apparently it's a fairly known issue on the zf transmissions. I shouldn't have bought an auto but that's besides the story. The car has 211k km on it, which is 131k miles.

I have done everything i can to diagnose the issues and all signs point to a rebuild for $$$. I think it is the E-clutch - I took apart the trans to replace the seals, air tested that pressure circuit, and it seemed to not hold pressure. Atthat point I didn't replace the solenoids, since I thought the clutch went bad. See this thread and my videos: https://www.e90post.com/forums/showp...8&postcount=13

I estimate it will cost about 1500 cad which is 1150 USD or so. It drives fine under most normal conditions except for the upshift from 4-5th under moderate to hard acceleration. This condition only occurs under 'spirited' driving - you wont see it 90% of the time in the car (Speeds of >120kph or 75mph). But the times that I want to have some fun, the issue is there. The reason I own this car is because it is a beautiful and comfortable car, but also allows me to experience a moderate level of driving performance when I desire. I can't really do that anymore with my trans issue and that disappoints me about this car.

I'm really set on the 2006 330i, it's a fantastic car. I want RWD with sport suspension, premium sound, and ideally no infotainment screen. I was really happy with my auto transmission (commuting, ease of access for other people, etc) until it just took a crap on me. I think it's because I drive it quite hard when i get the chance, open roads and stuff. That's where manuals really shine, but the auto was OK. I'm now faced with a $1500 or so repair bill to keep the car at the level of performance I want, and I would be hesitant to push the car anymore in that spirited manner. My car also needs a new windshield ($300-500) and possibly a rear damper. Total then for the car is going to be $1600-2k canadian.

Recently a used 6MT 2006 330i, basically the same car, was posted for sale for $5500. This car has 235k km or 146k miles, so about a full year's worth of driving more than my car has. It's one of the cleanest 13 year old cars I could expect to find. It turns out that the car i'm looking at is sold by one of the posters on this forum, and I'm thinking the car has been very well taken care of. That changes my mind a little, given that the car is likely to be in good shape.
However, per the seller, this car needs a rear wheel bearing due to hitting a pothole (could have wrecked other stuff too), and also needs front dampers (common on these cars at this age). Apparently there is also an oil leak (also common on these cars). I would expect the costs for these repairs to run around the same price as what I'm looking to spend to keep my auto car going. If I do switch, then I'll finally have that glorious manual trans BMW I've been longing for. But I am hesitant due to the additional 25k km or 15k miles, and the other potential problems that brings. At the same time, at this mileage, andyhing that would fail in the engine would have already gone I think, so I'm not too concerned. Also i'd have to pay the sales tax and registration on getting the new car.

So what would you do:
- Keep the current auto, don't repair the trans, dont drive spirited. Hope it lasts a few more years.
- Keep the current auto, repair the trans, drive spirited and worry that the trans will fail in the future.
- Sell the auto as-is, without fixing the trans, and get the 6MT. Hoping I could get between 5500 and 6500 for the auto, and talk the 6mt down to less than 5500. This would cover taxes and registration, but still have to pay for the repairs on the manual.
- Pay the $1500 to have the trans fixed, and then sell the car. Under this example I would get the most money for the automatic, but I doubt I would cover registration and taxes, and I'd still need to fix the 330i.

Or - other option - Sell the Auto and get a different car???

[Nando_e90]

What about solenoids? maybe replacing them fix the issue. I think that if the tranny works well 90% of the time and only when driving fast over 120km/h the issue occurs, maybe it is solenoid related. The solenoid responsable for the 4 - 5th upshift. IMO seems to be an electronic problem, not mechanical.

I also own a 2006 330i E90 with ZF auto transmission. When I bought it a year and a half ago, the tranny used to generate an error related to the 4 -5 th gear. Also, everytime I reached a stop and the tranny engaged 1st gear, there was a kick, as if someone just had hit you from behind. But, apart from that, tranny worked well. So, a year ago, on July 2018, I replaced all the mechatronic sleeves and all 7 solenoids, and problem desappeared since then.

[portlandareae28]

fix the car you have, could be getting into an even larger can of worms.

[leif20]

Originally Posted by Cala

What about solenoids? maybe replacing them fix the issue. I think that if the tranny works well 90% of the time and only when driving fast over 120km/h the issue occurs, maybe it is solenoid related. The solenoid responsable for the 4 - 5th upshift. IMO seems to be an electronic problem, not mechanical.

I also own a 2006 330i E90 with ZF auto transmission. When I bought it a year and a half ago, the tranny used to generate an error related to the 4 -5 th gear. Also, everytime I reached a stop and the tranny engaged 1st gear, there was a kick, as if someone just had hit you from behind. But, apart from that, tranny worked well. So, a year ago, on July 2018, I replaced all the mechatronic sleeves and all 7 solenoids, and problem desappeared since then.

Were you getting the 4F8A code? Did you see slip between 4-5 or did the transmission only throw that error code? I only see the error code come up after I have had the trans slip. It is quite noticeable and then using INPA I can read that code.

I had the transmission apart initially to check if the seals to the mechatronic were bad. I was able to air test the pressure circuit for the E-Clutch a couple of weeks ago. See my video for the pressure test here:

That dull whoosh noise is the hydraulic circuit not holding pressure, from what I understand. I'm inclined to believe it's the hydraulic circuit and not the solenoids. There are a couple of videos that show how to test for this, see my post here:
https://www.e90post.com/forums/showt...1#post24893311

I really want to think it's the solenoids since I bought a set of those too, but didn't install them once I heard that whooshing. To me that means the circuit is shot as the pressure is leaking somewhere. It should have more resistance to that compressed air if the circuit was in better shape. I don't want to throw away $300 if the problem is actually the bushing in the pump.


And to the second comment, I agree that I could be getting in to a can of worms with the newer car, people don't sell cars that are in perfect shape. I assume there are enough problems with that car to justify him not fixing it anymore, which is how this usually goes.

[smass]

You may want to contact ZF. They can be helpful.

https://www.zf.com/corporate/en_de/m...-inquiries.jsp

Bushing wear can happen but I think you need to run low on fluid to do damage.

[leif20]

Originally Posted by smassey321

You may want to contact ZF. They can be helpful.

https://www.zf.com/corporate/en_de/m...-inquiries.jsp

Bushing wear can happen but I think you need to run low on fluid to do damage.

I have read that the bushing can be damaged by loss of hydraulic pressure due to a worn valve body or seals. I suppose that running low on fluid could cause it also, but I don't think that's my issue in this case.

I sent ZF an email, I will post their response. At the moment I'm leaning towards doing the solenoids and seeing the effect.

EDIT - transcript with ZF:

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.

[Nando_e90]

Originally Posted by leif20

Were you getting the 4F8A code? Did you see slip between 4-5 or did the transmission only throw that error code? I only see the error code come up after I have had the trans slip. It is quite noticeable and then using INPA I can read that code.

I had the transmission apart initially to check if the seals to the mechatronic were bad. I was able to air test the pressure circuit for the E-Clutch a couple of weeks ago. See my video for the pressure test here: https://photos.app.goo.gl/BiLbnJS6nZ86DrUr6

That dull whoosh noise is the hydraulic circuit not holding pressure, from what I understand. I'm inclined to believe it's the hydraulic circuit and not the solenoids. There are a couple of videos that show how to test for this, see my post here:
https://www.e90post.com/forums/showt...1#post24893311

I really want to think it's the solenoids since I bought a set of those too, but didn't install them once I heard that whooshing. To me that means the circuit is shot as the pressure is leaking somewhere. It should have more resistance to that compressed air if the circuit was in better shape. I don't want to throw away $300 if the problem is actually the bushing in the pump.


And to the second comment, I agree that I could be getting in to a can of worms with the newer car, people don't sell cars that are in perfect shape. I assume there are enough problems with that car to justify him not fixing it anymore, which is how this usually goes.

I don't remember exactly the error that was throwing my transmission (by then I didn't have INPA and a mechacnic read the faults) but was something like that 4F8A. I think it was the same. And, yes, it used to slipped but sometimes, not like yours that you can even predict when it's going to happen. I assume that you have done a large research about this problem, but if not, thats what I would do, trying to identify people who have had the same issue and how do they solved it.

In my case, maybe the problem would've been solved by replacing just the sleeves, specially the one with a square shape because I understand that is the one that can generate error code. But I read in a site about ZF transmission that the solenoids replacement is not a bad idea even if yours are still working, says that "you would be surprised how transmission shifts with new solenoids". So I decided to replace them anyway and no regrets since then. Well.. in my case, a that time I had only a few months with the car and selling it wasn't whithin my options.

This sites are very good about ZF transmission (mainly the 1st one). Maybe you have already seen it, but if not, it can be very helpful.

https://sayyarti.wordpress.com/2015/...ission-issues/

https://www.transmissionrepaircostgu...sion-solenoid/

[nsjames]

sonnax has a bunch of info on these as well.

https://www.sonnax.com/units/214-zf6hp21

[leif20]

I think my biggest apprehension with just 'replacing the solenoids' is that I'm basically throwing parts at the problem, without having an idea whether or not it will fix it. It could be the bushing wear, valve body wear, or clutch pack wear. I don't have the time to diagnose and fix valve body wear, and I don't have the tools or expertise to deal with the other issues so I'd take it to a trans repair shop. A trans repair shop would also be able to diagnose the issue, but they quoted me $900 CAD to remove, disassemble, diagnose, and then reinstall (without fixing the problem, fixing the problem will no doubt cost more). If it's not the solenoids I really would hate to drop $300 in parts and then a half day's worth of labor on something that wouldn't fix the problem and still be hesitant to drive the car hard.

It looks like if I'm set on getting a car to drive hard I should just get a newer car! That way I won't have to worry about the trans failing immediately. It probably doesn't make sense to sell my car and get the same model with higher mileage, a known list of issues that need replacing, and hope i'll be able to drive it hard. Maybe it's time to grow up and stop using the street/highway like a racetrack, and just enjoy my car for what it is. I think my trans would last a decent amount longer if I were to take better care of it that way. But the power delivery of the N52 is so tempting!

[hassmaschine]

6mt swap.

[leif20]

Updates on my situation:

TL;DR - Solenoids have solved the slip issue, it seems. Cost was around $650 and a day of my own labour. I'm keeping the car, for now.

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

Here are some threads/posts that convinced me to do the solenoids:
https://www.bimmerfest.com/forums/sh...light=solenoid
https://www.bimmerfest.com/forums/sh...light=solenoid
https://5series.net/forums/diy-do-yo...137584/page10/

[mecheng77]

Glad to hear it worked out, I guess only the 330's have the ZF. I'm glad I have the GM trans.

[sowbmw]

Did you reset the transmission software using ISTA? In my e46 330ci I had transmission issues as well. Ended up changing out solenoids but issue persisted. After resetting the software, the issue was gone.

[BadContrakt]

I've been in the same boat and I opted to fix the car I already have and do not regret it at all.

The way I looked at it was, simply... I already own this car and know this car and know its pros and cons. I have a good idea of what it'll take to get it into the condition I want and if I swap keys I could not only lose money on the transaction but also, the second vehicle could need even more repairs. It's USUALLY a wash but sometimes you get bit. I tend to stray away from getting bit. I put something like 2500 into my car and it's MINT. Very happy with my decision.

[BadContrakt]

Originally Posted by leif20

If you buy a high mileage e90 with a ZF auto, at the first sign of trans issues I would recommend this.

From post 14 above ^^^ I actually, in my 2500 dollars of "repairs and maintenance to get the car in the condition I want it in" was a solenoids, seals, fluid, and filter transmission service. I used a DIY I believe I found on this forum and everything went really well. The car shifted like 20% better at first. Then like 30-40% better after a couple days. Then after like a solid week of driving to work and back, my transmission (141,000 AMURICA MILES) damn near shifts like a CVT. I also did some driveshaft service, coilovers, other minor fixes on bips and bops, and the car is sitting in a great place right now.

I was having some high gear slippy shifts under load and also some very clunky and uncomfortable low end gear shifts when not under load. The car would lurch really hard if I was just cruising slowly and it would upshift from 2nd to 3rd for example. LURCH FORWARD. Not anymore! Mine is a ZF6HP21X.

[leif20]

Originally Posted by BadContrakt

I was having some high gear slippy shifts under load and also some very clunky and uncomfortable low end gear shifts when not under load. The car would lurch really hard if I was just cruising slowly and it would upshift from 2nd to 3rd for example. LURCH FORWARD. Not anymore! Mine is a ZF6HP21X.

Since the repairs have you been back up in to the regions where you used to experience slip? 4-5 or 5-6 slip under higher throttle?

This past weekend I had a road trip so I was able to open it up a bit more, and it certainly seems like my shifts are completing correctly. When I'm pushing the car like I used to it's taking what I throw at it, No slip thankfully. Has this been your experience too? Does it seem like your trans is just as good as new? I'm quite happy I did this, the to tie the thread back I'm keeping the car for now, and still in love with it.

[BadContrakt]

Originally Posted by leif20

Since the repairs have you been back up in to the regions where you used to experience slip? 4-5 or 5-6 slip under higher throttle?

This past weekend I had a road trip so I was able to open it up a bit more, and it certainly seems like my shifts are completing correctly. When I'm pushing the car like I used to it's taking what I throw at it, No slip thankfully. Has this been your experience too? Does it seem like your trans is just as good as new? I'm quite happy I did this, the to tie the thread back I'm keeping the car for now, and still in love with it.

I have, and do, push the car often and it shifts close-to-new, yes. Doing all of that service to my transmission, above all the other maintenance I did, was hands down the best thing I did for that car.