BMW 1-Series Forum (F20) 135i - 1Addicts.com > Second Generation 1 Series Forum > 2012 BMW 1-Series Sporthatch (F20) Discussion > ZF 8HP problems
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      04-13-2017, 02:06 AM   #45
harkes
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Very interesting article about the ZF8HP!

What an amazing piece of mechanics

Quote from the page:
Chris,

The inertia inside an automatic transmission is actually quite low. Engine rotational inertia tends to range from 0.2 to 0.45 kg-m^2. For comparison, the 5th gear inertia is somewhere in the region of 0.04 to 0.08 kg-m^2.

So while fifth gear operation is complicated, the losses are not that bad. I would estimate the losses at 5th gear and 2000 rpm with 20 hp road load to be no more than 1.5 hp.

Please remember, even when planetary gear sets are along for the ride, they still contribute to the inertia.

http://www.thetruthaboutcars.com/201...eed-automatic/
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      04-13-2017, 04:02 AM   #46
ovekvam
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Quote:
Originally Posted by harkes View Post
Very interesting article about the ZF8HP!
Indeed. Very impressive. As a hater of automatic transmissions, I can feel my hate towards this unit fading a little bit here now! :-)
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      04-13-2017, 05:43 AM   #47
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Its an outstanding piece of machinery. My zf feels flawless in every condition (the standard one), with 28k km.

The perceived direct transmission between motor and wheels, seems from a very wise choice of mechanical gearing, and the low inertia claims feels like true.

What amazes me the most is the hydraulic torque converter, because it feels like a nicely driven clutch, engaging smoothly, and locked once engaged... all through a fluid with no friction pads; it is amazing.

I drive mt cars regularly, love to pilot the clutch, but this zf is superior in all sense for a modern car daily drive.

I think theres a risk of damaging the first gears if the driver is not careful in stopping before reversing, parking, and abusing first gear with full throttle, as in all transmissions, so second hand cars could have issues due to mishandling.
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      04-18-2017, 07:41 PM   #48
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Got a 2016 m135i. No issue until firstinspection where they found a slight oil leak/seepage along the edge of transmission sump. I was told it's ok and will be replace under warranty. Anyone has the same issue/experience? The reason I was given is the seal did not seat properly... But without taking it apart how do they know... And the guy is just servicea advisor.
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      10-25-2017, 04:21 PM   #49
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Got a 2017 118i m sport with the 8speed today for wife and kids. Had a rental 2017 golf dsg for a week before today. What a smooth and precise car the golf. But on the 118... What the hell is going on between 1st and 3rd. In city driving i feel the car is pushing me too much for no reason im pushing throtle smoothly nd the shifts feel uncoordinated with the engine jerky also. Chassis is amazing engine feels like its over working although u can hear the turbos alot which is nice. On highway at 160kmh is much smoother and comfortable than my m3. Tried all modes manual sport + traction off... i feel this car is amazing but they fucked it with the transmission.
Ill try tune but i doubt it ll do much? Very unfortunate from bmw that they fucked the last units of rwd 1 series on a petrol engine specially they suouldve sent it off with a proper auto transmission.
Thanks
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      10-25-2017, 09:28 PM   #50
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Quote:
Originally Posted by Fp77 View Post
Got a 2017 118i m sport with the 8speed today for wife and kids. Had a rental 2017 golf dsg for a week before today. What a smooth and precise car the golf. But on the 118... What the hell is going on between 1st and 3rd. In city driving i feel the car is pushing me too much for no reason im pushing throtle smoothly nd the shifts feel uncoordinated with the engine jerky also. Chassis is amazing engine feels like its over working although u can hear the turbos alot which is nice. On highway at 160kmh is much smoother and comfortable than my m3. Tried all modes manual sport + traction off... i feel this car is amazing but they fucked it with the transmission.
Ill try tune but i doubt it ll do much? Very unfortunate from bmw that they fucked the last units of rwd 1 series on a petrol engine specially they suouldve sent it off with a proper auto transmission.
Thanks
+1

The dual-clutches from both VW and BMW are wayyyyy better than the ZF8 (in a BMW).
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      05-07-2018, 04:52 AM   #51
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zf km

Quote:
Originally Posted by harkes View Post
Hi there

(trying to collect all ZF related in one thread)

Seems we are more people not entirely satisfied with the "oh so amazing" ZF. My biggest complain is the jerky shifting 2nd-1st-2nd during slow driving. The ZF is also not 100% smooth at all times like my friends DCT (that is a freaking amazing gearbox!!!).

What do you guys have to say? Any remedy? A software update under way?



HI

km? how much do you have! zf is saying to change the oil between 80k and 120k depending the driving style! after i changed mine the 1 to 2 was very smooth!
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      08-30-2019, 03:53 PM   #52
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Sorry this is my first post so can’t start a new thread.

I have a 135i auto. Today I was in eco and needed to plant my foot so around 30/40mph did so, it kicked down a gear went to around 6,500rpm but wouldn’t change up. I had to manually Change the gear up. No lights have come up on the dash. I have since put the car in sport mode and it goes to around 6,500 rpm but won’t change up. It seems all fine in eco and comfort as long as you don’t plant your foot. If you do so you have to manually change up. Any ideas only had the car a few months I’m not sure but it may also seem down on power in sport mode.
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