ZF 8HP transmission hard shifting 1-2 when cold

[MCompact]

Originally Posted by cristiancc

I am bothered by the automatic transmission on my 2012 BMW 5. I bought the car used and although I serviced the transmission, I do not like the way it shifts. When transmission is cold the 1-2-3 shifts make the car slow down and then lunge, they are not smooth. After a few miles of driving, the shifts are smooth, but only when in Drive mode. If I manually upshift, even at the same rpm as it's done automatically in the Drive mode the hard shift is felt again. And it's stronger as I shift at a higher rpm. 1st to 2nd gear has the hardest shifts. No errors present in INPA. Has anyone been facing this issue?

Have the transmission adaptations been reset?

 

[JTK]

I have read of Ram 1500 trucks with the ZF 8s have this complaint. On some, valve bodies were replaced, others, the whole transmission was replaced IIRC. This was on 8HP70 equipped trucks. I haven't heard of this concern with the 8HP45, which I assume this BMW has and is what my V6 powered Ram 1500 has. I know mine can lurch a bit from 1-2 after cold start when coasting out of the parking spot, but I've had many ATs that would do that.

 

[Env1ous]

My f150 was shifting odd and I needed to clean the MAF/MAP sensors. It has a ZF based trans as well. the 6R80.

 

[SteveSRT8]

Originally Posted by Env1ous

My f150 was shifting odd and I needed to clean the MAF/MAP sensors. It has a ZF based trans as well. the 6R80.

That was what I was alluding to above. If the TB is sticky/dirty or some sensor like the IAT is acting up they can affect shifting, especially when just started. My only point was before replacing valve bodies or entire trans...

 

[nascarnation]

My guess is they have a poor software characterization for colder temps. The parameters that the controller uses to command a pressure profile for the feed to the applying clutch have to be adjusted for performance over the temp/viscosity spectrum. It may not be a mechanical problem at all. I wonder if BMW or ZF has released any software updates since yours was manufactured?

 

[edyvw]

Originally Posted by nascarnation

My guess is they have a poor software characterization for colder temps. The parameters that the controller uses to command a pressure profile for the feed to the applying clutch have to be adjusted for performance over the temp/viscosity spectrum. It may not be a mechanical problem at all. I wonder if BMW or ZF has released any software updates since yours was manufactured?

I drove numerous BMW's with ZF8, and if something comes to perfect automatic transmission programming is BMW ZF8 programming. No issues in cold weather with shifting at all.

 

[SteveSRT8]

I fail to understand software "characterization". But software strategies are wildly manufacturer dependent, and often times a reflash will help. But OP's mileage suggests some deposits are likely. I also agree that BMW shift programming is nearly perfect. I would also say that my 14 RAM 5.7/8 speed ZF combo is nearly perfect, it just always is smooth and positive. Shifts are super fast yet smooth. Maybe you just need to reset the adaptives and drive the thing hard for a bit...

 

[gomes512]

Had a 16 Ram with 8HP70 that shifted violently from 1-2 when cold. Whole truck would feel like it was hitting something. Drove that for a few months and the dealer did a software update that softened the shifts. Still would do it randomly though. Last dealer visit I asked them to look for additionally updates, tech claimed that there were none and he only did a "quick relearn". Completely different feeling vehicle now.

 

[Johnnycage]

Hi, I have the exact same issues as yours and i would wonder have you found the solution at the end? What is going wrong with the gearbox? I have no code but the shifting 1-2-3 is noticeable specially 1-2 . Many thanks Johnny

 

[charmer37]

I don't know much about the ZF 8 speed transmissions but if it's similar to the 6HP transmission I had to drop the Mechatronic valve body and replace a few seals and the plug adapter, After I replaced those parts along with a new pan/filter and fluid my transmission was like new. Could also be the solenoids but you mention you didn't have any codes.

 

[bumwah]

Hello ya'll..... I have a 2012 BMW 535i, just turned over 50,000 miles. Since I bought it used at 28k, from a Mercedes Benz Dealership, it began its life of under delivering the driving experience I thought I was going to have based on my previous BMW vehicles. The main issue in the beginning was a rough idle, the fix for that was to raise the engine rpm's through ISTA D or A software. Idle is smoother now, but the car has also shown signs of rough shifting. Downshifting from 2nd to 1st at times feels like I am getting rear ended, it sort of stutters for a split second then slams into gear. Also, when taking off from a stop, there is a delay or dead spot, then all of a sudden the car jerks into gear, completely an issue and not safe IMO. I would say its much worse when cold, but still present when fully warmed up. I have been told by more than one shop that the fluid level and quality was fine, and if there are not any trouble codes there isnt much they would/could do. I have had my software checked, they say it is up to date, they have reset transmission values more than once, all symptoms seem to eventually return the same or worse. From the beginning, I read/thought there was something wrong with my NIC (Neutral Idle Control), but the last year or so I have been leaning towards sticking/failing solenoid valves. I am not sure if just the solenoids are available for this shiftbox, as I have heard they have to buy the entire mechatronics unit for something like $2500, I am trying to avoid this.

 

[BMWTurboDzl]

Originally Posted by bumwah

Hello ya'll..... I have a 2012 BMW 535i, just turned over 50,000 miles. Since I bought it used at 28k, from a Mercedes Benz Dealership, it began its life of under delivering the driving experience I thought I was going to have based on my previous BMW vehicles. The main issue in the beginning was a rough idle, the fix for that was to raise the engine rpm's through ISTA D or A software. Idle is smoother now, but the car has also shown signs of rough shifting. Downshifting from 2nd to 1st at times feels like I am getting rear ended, it sort of stutters for a split second then slams into gear. Also, when taking off from a stop, there is a delay or dead spot, then all of a sudden the car jerks into gear, completely an issue and not safe IMO. I would say its much worse when cold, but still present when fully warmed up. I have been told by more than one shop that the fluid level and quality was fine, and if there are not any trouble codes there isnt much they would/could do. I have had my software checked, they say it is up to date, they have reset transmission values more than once, all symptoms seem to eventually return the same or worse. From the beginning, I read/thought there was something wrong with my NIC (Neutral Idle Control), but the last year or so I have been leaning towards sticking/failing solenoid valves. I am not sure if just the solenoids are available for this shiftbox, as I have heard they have to buy the entire mechatronics unit for something like $2500, I am trying to avoid this.

Try contacting this guy for parts. Has anyone actually checked the fluid vs looking for leaks? I suspect it's possible that the fluid was low from the factory. IMO I would just change the fluid and re-evaluate: ZF8HP ATF Change Kit

 

[bumwah]

Try contacting this guy for parts. Has anyone actually checked the fluid vs looking for leaks? I suspect it's possible that the fluid was low from the factory. IMO I would just change the fluid and re-evaluate: ZF8HP ATF Change Kit[/quote] So I have been to a few shops in town, I have been told the fluid looks good, one shop did some sort of analysis of it. All three shops told me the level was fine. I see no evidence of fluid leaking outside the transmission case. But could be internal leakage i guess. The link to ZF parts is nice, but they just dont have the 8 speed parts like they do for the 6 speed transmissions. Ill tell you what, when my car is cold, it sure sounds like a starving pump until it warms up. Not sure if its low fluid level causing that, bad seals somewhere, or what? It really feels like my car has a transmission fluid pressure issue, for some reason it cannot smoothly up or down shift (worse when cold) and I have this inclination that it is the solenoids not doing their jobs correctly. Or its software, or its HPFP, or its injectors..............I just miss my E39. I forgot to mention on my initial post, that I ended up having one Drivetrain Malfunction come up. It came after a quick accelleration from a stop, it gave me reduced engine power and the car was shaking really bad, especially when stopped. I turned the engine off for a few minutes and the shaking stopped and the Drivetrain Malfunction warning went away. super weird. OK, feedback please and thank you!!

 

[BMWTurboDzl]

Originally Posted by bumwah

Try contacting this guy for parts. Has anyone actually checked the fluid vs looking for leaks? I suspect it's possible that the fluid was low from the factory. IMO I would just change the fluid and re-evaluate: ZF8HP ATF Change Kit

So I have been to a few shops in town, I have been told the fluid looks good, one shop did some sort of analysis of it. All three shops told me the level was fine. I see no evidence of fluid leaking outside the transmission case. But could be internal leakage i guess. The link to ZF parts is nice, but they just dont have the 8 speed parts like they do for the 6 speed transmissions. Ill tell you what, when my car is cold, it sure sounds like a starving pump until it warms up. Not sure if its low fluid level causing that, bad seals somewhere, or what? It really feels like my car has a transmission fluid pressure issue, for some reason it cannot smoothly up or down shift (worse when cold) and I have this inclination that it is the solenoids not doing their jobs correctly. Or its software, or its HPFP, or its injectors..............I just miss my E39. I forgot to mention on my initial post, that I ended up having one Drivetrain Malfunction come up. It came after a quick accelleration from a stop, it gave me reduced engine power and the car was shaking really bad, especially when stopped. I turned the engine off for a few minutes and the shaking stopped and the Drivetrain Malfunction warning went away. super weird. OK, feedback please and thank you!! [/quote] ISTA-D didn't give you any codes? Are there any software recalls for your vehicle? If you're interested in some personalized service I would pull codes and then ask this GUY along with a small donation for his time.

 

[bumwah]

~~~~~ISTA-D didn't give you any codes? Are there any software recalls for your vehicle? If you're interested in some personalized service I would pull codes and then ask this GUY along with a small donation for his time.~~~~~~quoted ISTA-D hasnt been hooked up/used since before my drivetrain malfunction came up. But at the time there were no codes, all software was up to date, according to "them". One thing they did do with ISTA-D was raise some of the idle rpm parameters. The car had a rough idle at 20k miles when I purchased it used. After both in town BMW dealerships couldnt get rid of the rough idle, sometimes an audible knock it was so rough, an independent shop in town changed idle rpms with ISTA-D and it smoothed it out. BUT, maybe having this increased RPMs has made my rough shifting worse..... i am not sure. I feel like i need to return the car to all stock rpm parameters, and do a transmission fluid service and go from there.

 

[BMWTurboDzl]

Originally Posted by bumwah

~~~~~ISTA-D didn't give you any codes? Are there any software recalls for your vehicle? If you're interested in some personalized service I would pull codes and then ask this GUY along with a small donation for his time.~~~~~~quoted ISTA-D hasnt been hooked up/used since before my drivetrain malfunction came up. But at the time there were no codes, all software was up to date, according to "them". One thing they did do with ISTA-D was raise some of the idle rpm parameters. The car had a rough idle at 20k miles when I purchased it used. After both in town BMW dealerships couldnt get rid of the rough idle, sometimes an audible knock it was so rough, an independent shop in town changed idle rpms with ISTA-D and it smoothed it out. BUT, maybe having this increased RPMs has made my rough shifting worse..... i am not sure. I feel like i need to return the car to all stock rpm parameters, and do a transmission fluid service and go from there.

Sounds like a plan. Be sure to post back.