Second Gen 8AT gearbox creep.

Flyboy777 · 07-09-2016, 06:51 AM

How much 'creep' do you get while holding it in 1st on the brakes?
This is related to the new 8HP50 as fitted since the LCI to the lower torque models not 330D etc which have the 8HP75 although I am sure it should perform the same.
Reason for asking is the ZF blurb for the updated gearbox states creep is eliminated to reduce fuel consumption whilst idling in gear and it is no longer necessary to brake against the drive while stationary.
My Oct 2015 LCI 320D creeps as much as any previous car so wondered if it was right.

http://www.car-engineer.com/second-g...-transmission/

"Meanwhile, a further innovative function minimizes the creeping torques: A clutch is now fully opened during deceleration and when the vehicle is stationary. “Consequently, it is no longer necessary to ‘brake’ against the drive,” explains Jürgen Greiner. Another positive effect is that the oil pump belonging to the ZF automatic transmission works with a system pressure that has been reduced from 5 to 3.5 bar and, as a result, requires less energy overall."

HighlandPete · 07-09-2016, 10:01 AM

Quote:

Originally Posted by Flyboy777

How much 'creep' do you get while holding it in 1st on the brakes?

My Oct 2015 LCI 320D creeps as much as any previous car so wondered if it was right.

I'm intrigued by what you say regarding "any previous car". Does that include the auto models with NIC (Neutral Idle Control) and previous models where there was much more drag to be held on the brakes.

NIC, as in all 1st generation 8-speed autos, virtually disengages the TC anyway. Something like a 90% reduction in drag while NIC is active in stationary conditions. But you still hold the car on the brake as it is the 'trigger' for NIC function. Ease off the brake and it seamlessly engages again and creeps forward. If the latest improvements to NIC are still brake instigated, it may not show up much different in feel to the 1st generation.

Personally haven't driven the latest generation gearbox, so have no personal experience on what the stationary feel is like.

JustChris · 07-09-2016, 12:06 PM

Every one of my ZF BMW autos has crept. Only the DCT does not and obviously different subject.

Current car is an LCI F30 so I assume might be this latest box your referring to? Definitely creeps if brake is not depressed.

Flyboy777 · 07-09-2016, 02:56 PM

Thanks guys,

What Pete says makes perfect sense-- the TC re engages as you lift off the brake pedal hence the creep but you weren't necessarily holding the brakes against the drive once stationery.
The phrase in my link which says no longer necessary to brake against the drive, confused me but now I think that means whilst decelerating the drive disengages.
Basically it feels just like any other auto I have driven which is a good thing, was just checking if mine was the same as any others on here which it appears is the case as JustChris's behaves the same.
It's my first ZF 8AT, last auto was an Audi A4.

07-09-2016, 06:51 AM	#1
Flyboy777 Private First Class 76 Rep 181 Posts Drives: 2015 F31 320D LCI Join Date: Apr 2014 Location: Hampshire iTrader: (0)	Second Gen 8AT gearbox creep. How much 'creep' do you get while holding it in 1st on the brakes? This is related to the new 8HP50 as fitted since the LCI to the lower torque models not 330D etc which have the 8HP75 although I am sure it should perform the same. Reason for asking is the ZF blurb for the updated gearbox states creep is eliminated to reduce fuel consumption whilst idling in gear and it is no longer necessary to brake against the drive while stationary. My Oct 2015 LCI 320D creeps as much as any previous car so wondered if it was right. http://www.car-engineer.com/second-g...-transmission/ "Meanwhile, a further innovative function minimizes the creeping torques: A clutch is now fully opened during deceleration and when the vehicle is stationary. “Consequently, it is no longer necessary to ‘brake’ against the drive,” explains Jürgen Greiner. Another positive effect is that the oil pump belonging to the ZF automatic transmission works with a system pressure that has been reduced from 5 to 3.5 bar and, as a result, requires less energy overall."
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07-09-2016, 12:06 PM	#3
JustChris General 17488 Rep 25,115 Posts Drives: Tesla MYRWD Join Date: Jul 2013 Location: UK iTrader: (0)	Every one of my ZF BMW autos has crept. Only the DCT does not and obviously different subject. Current car is an LCI F30 so I assume might be this latest box your referring to? Definitely creeps if brake is not depressed. __________________ My car made front page of Bimmerpost
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07-09-2016, 02:56 PM	#4
Flyboy777 Private First Class 76 Rep 181 Posts Drives: 2015 F31 320D LCI Join Date: Apr 2014 Location: Hampshire iTrader: (0)	Thanks guys, What Pete says makes perfect sense-- the TC re engages as you lift off the brake pedal hence the creep but you weren't necessarily holding the brakes against the drive once stationery. The phrase in my link which says no longer necessary to brake against the drive, confused me but now I think that means whilst decelerating the drive disengages. Basically it feels just like any other auto I have driven which is a good thing, was just checking if mine was the same as any others on here which it appears is the case as JustChris's behaves the same. It's my first ZF 8AT, last auto was an Audi A4.
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