ZF8 Jerk when shifting from 5th to 6th gear when cold ONLY

oczko98 · 11-22-2022, 08:18 AM

Hello,
I've been having a weird jerk for a while now, happens only when shifting from 5th to 6th gear.
I could describe it as a punch, a kick.
Occurs only when the trans oil is cold.

As soon as the oil in the gearbox warms up above 60 degrees, everything is fine, you can't feel the change from 5th to 6th.
The shifting of all other gears is perfect, cold/warm oil (no jerks, kicks, etc).

The mileage at this moment is almost 200k km, during this time the oil was changed twice (at 100k km and at 192k km) - always everything from zf.
Adaptation at exchanges done.
The pressures and filling times are perfect.

Anyone have any idea what I can do to improve the change from 5 to 6 on cold oil trans?

oczko98 · 11-28-2022, 04:50 PM

Bump.

Wires · 11-28-2022, 04:55 PM

Not a transmission expert, but that sounds like an issue with the 6th gear clutch pack. Clutch materials tend to be more "grippy" when cold.

Do you have xHP? Their software shows clutch pack delays/pressures which can help point to an issue.

zeikei · 11-28-2022, 05:11 PM

Are you absolutely sure that the oil level is correct and it has been set according to ISTA procedure?

krith · 11-28-2022, 05:32 PM

At 192 km, was there any issue?
If the issue is posted, a drain and fill of fluids, then I would be keen on checking fluid levels.

Was the transmission pan/filter replaced at the same time? -This will make me sad if not.

This jerk sensation, is it more noticeable when at a steady throttle input going from 5 to 6 and lessens with a more aggressive throttle input? i.e feels smoother when you apply more power.

Let's start here.

oczko98 · 11-28-2022, 05:40 PM

Quote:

Originally Posted by zeikei

Are you absolutely sure that the oil level is correct and it has been set according to ISTA procedure?

Yes.
Oil level checked at 40*c.
With the air conditioning on, the was car running, the gearbox in Park.
Each gear thrown before.

Was missing about 350ml. Filled with original Zf fluid for 8hp.

oczko98 · 11-28-2022, 05:44 PM

Quote:

Originally Posted by krith

At 192 km, was there any issue?
If the issue is posted, a drain and fill of fluids, then I would be keen on checking fluid levels.

Was the transmission pan/filter replaced at the same time? -This will make me sad if not.

This jerk sensation, is it more noticeable when at a steady throttle input going from 5 to 6 and lessens with a more aggressive throttle input? i.e feels smoother when you apply more power.

Let's start here.

Fluid level is correct now. It was missing around 350ml. Filled with original zf fluid for 8hp.
Sure, original pan/filter and zf oil at the same time.
Feels smother when it changes around 2k rpm.
When I apply more power, like you said.
Is it normal? Other gears are great.

oczko98 · 11-28-2022, 05:46 PM

Quote:

Originally Posted by Wires

Not a transmission expert, but that sounds like an issue with the 6th gear clutch pack. Clutch materials tend to be more "grippy" when cold.

Do you have xHP? Their software shows clutch pack delays/pressures which can help point to an issue.

Never had xHP so trans soft is stock.
Currently running on bms stage 1.

thejeremyman9 · 11-28-2022, 06:03 PM

Datalog the shift and see if there is something weird going on with torque limits. Also check the transmission adaptation values as wires mentioned.

oczko98 · 11-28-2022, 06:21 PM

Quote:

Originally Posted by thejeremyman9

Datalog the shift and see if there is something weird going on with torque limits. Also check the transmission adaptation values as wires mentioned.

Transmission adaptations are great.
How I can datalog? Don't Have bm3 etc. Is there any program on PC or android/iOS?
I have enet & vgate obd.

Edit.
Found that testo should work with enet. Will check it later

oczko98 · 11-29-2022, 06:22 AM

I have read that the problem may be related with BMS Stage 1. Will give some info soon.
Any other ideas?

Wires · 11-29-2022, 07:48 AM

Quote:

Originally Posted by oczko98

Transmission adaptations are great.
How I can datalog? Don't Have bm3 etc. Is there any program on PC or android/iOS?
I have enet & vgate obd.

Edit.
Found that testo should work with enet. Will check it later

Yes, that's what I see in the xHP app.

oczko98 · 11-29-2022, 08:54 AM

Quote:

Originally Posted by Wires

Quote:

Originally Posted by oczko98

Transmission adaptations are great.
How I can datalog? Don't Have bm3 etc. Is there any program on PC or android/iOS?
I have enet & vgate obd.

Edit.
Found that testo should work with enet. Will check it later

Yes, that's what I see in the xHP app.

I use bimmerlink

So the trans values are good I think.

krith · 11-29-2022, 11:27 AM

350ml Low on ATF is not great; however, not detrimental for a short period of time.

Since the rest of the other checks look fine.

Seems like you might have an issue with clutch packs. Seeing how the rest of the shifts are fine.

One possible solution is to perform another flush fill with a new pan/filter and use an ATF with greater cleaning properties like Motul.

I personally use OEM ZF8 ATF, but the BMW performance shop I go to recommends Motul. Just an idea.
If the 6th gear clutch pack is going, might as rebuild them all if that is the case.

LA1Z24 · 11-29-2022, 01:59 PM

I had odd shifting issues running BM3 multimap. This is on a brand new, built PureDrivetrains transmission. Went to stage 2+ e30 and the issue is gone.

oczko98 · 11-29-2022, 04:16 PM

Quote:

Originally Posted by krith

350ml Low on ATF is not great; however, not detrimental for a short period of time.

Since the rest of the other checks look fine.

Seems like you might have an issue with clutch packs. Seeing how the rest of the shifts are fine.

One possible solution is to perform another flush fill with a new pan/filter and use an ATF with greater cleaning properties like Motul.

I personally use OEM ZF8 ATF, but the BMW performance shop I go to recommends Motul. Just an idea.
If the 6th gear clutch pack is going, might as rebuild them all if that is the case.

Interesting thing is that the shifts (5th->6th) around 1.8k-2k rpm are perfect (cold trans oil).
Just checked it.

:

thejeremyman9 · 11-29-2022, 06:59 PM

Quote:

Originally Posted by oczko98

Interesting thing is that the shifts (5th->6th) around 1.8k-2k rpm are perfect (cold trans oil).
Just checked it.

:

I honestly wouldnt lose sleep about it in its current state. You already did more transmission service and checking than most do. Just monitor and address later if the problem becomes worse or other symptoms arise.

Can also run XHP since its great anyways and see if software helps

oczko98 · 11-30-2022, 05:21 AM

Quote:

Originally Posted by thejeremyman9

Quote:

Originally Posted by oczko98

Interesting thing is that the shifts (5th->6th) around 1.8k-2k rpm are perfect (cold trans oil).
Just checked it.

:

I honestly wouldnt lose sleep about it in its current state. You already did more transmission service and checking than most do. Just monitor and address later if the problem becomes worse or other symptoms arise.

Can also run XHP since its great anyways and see if software helps

Yeah, Thanks for advice

I'm trying to shift into 6th gear with a little more throttle and it really seems to work.

I'll unplug BMS in my free time.
I also cleaned maf & map sensor yesterday.

Will give more info soon.

11-22-2022, 08:18 AM	#1
oczko98 Private 16 Rep 81 Posts Drives: F30 328i 2012 Join Date: Dec 2021 Location: Poland iTrader: (0) Garage List 2012 F30 328i [10.00]	ZF8 Jerk when shifting from 5th to 6th gear when cold ONLY Hello, I've been having a weird jerk for a while now, happens only when shifting from 5th to 6th gear. I could describe it as a punch, a kick. Occurs only when the trans oil is cold. As soon as the oil in the gearbox warms up above 60 degrees, everything is fine, you can't feel the change from 5th to 6th. The shifting of all other gears is perfect, cold/warm oil (no jerks, kicks, etc). The mileage at this moment is almost 200k km, during this time the oil was changed twice (at 100k km and at 192k km) - always everything from zf. Adaptation at exchanges done. The pressures and filling times are perfect. Anyone have any idea what I can do to improve the change from 5 to 6 on cold oil trans?
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11-28-2022, 04:50 PM	#2
oczko98 Private 16 Rep 81 Posts Drives: F30 328i 2012 Join Date: Dec 2021 Location: Poland iTrader: (0) Garage List 2012 F30 328i [10.00]	Bump.
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11-28-2022, 04:55 PM	#3
Wires Brigadier General 1644 Rep 4,872 Posts Drives: 2016 340i xDrive Join Date: Apr 2008 Location: Calgary iTrader: (0)	Not a transmission expert, but that sounds like an issue with the 6th gear clutch pack. Clutch materials tend to be more "grippy" when cold. Do you have xHP? Their software shows clutch pack delays/pressures which can help point to an issue.
	Appreciate 0 Quote

11-28-2022, 05:11 PM	#4
zeikei Second Lieutenant 125 Rep 298 Posts Drives: F36 Join Date: May 2018 Location: Finland iTrader: (0)	Are you absolutely sure that the oil level is correct and it has been set according to ISTA procedure?
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11-28-2022, 05:32 PM	#5
krith Old Member 125 Rep 81 Posts Drives: 435i F36, M-Sport 2015 Join Date: May 2013 Location: Raleigh, NC iTrader: (0)	At 192 km, was there any issue? If the issue is posted, a drain and fill of fluids, then I would be keen on checking fluid levels. Was the transmission pan/filter replaced at the same time? -This will make me sad if not. This jerk sensation, is it more noticeable when at a steady throttle input going from 5 to 6 and lessens with a more aggressive throttle input? i.e feels smoother when you apply more power. Let's start here. __________________ Car Stuff
	Appreciate 1 oczko9816.00 Quote

11-28-2022, 06:03 PM	#9
thejeremyman9 Major General 4358 Rep 7,591 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	Datalog the shift and see if there is something weird going on with torque limits. Also check the transmission adaptation values as wires mentioned.
	Appreciate 1 oczko9816.00 Quote

11-29-2022, 06:22 AM	#11
oczko98 Private 16 Rep 81 Posts Drives: F30 328i 2012 Join Date: Dec 2021 Location: Poland iTrader: (0) Garage List 2012 F30 328i [10.00]	I have read that the problem may be related with BMS Stage 1. Will give some info soon. Any other ideas?
	Appreciate 0 Quote

11-29-2022, 11:27 AM	#14
krith Old Member 125 Rep 81 Posts Drives: 435i F36, M-Sport 2015 Join Date: May 2013 Location: Raleigh, NC iTrader: (0)	350ml Low on ATF is not great; however, not detrimental for a short period of time. Since the rest of the other checks look fine. Seems like you might have an issue with clutch packs. Seeing how the rest of the shifts are fine. One possible solution is to perform another flush fill with a new pan/filter and use an ATF with greater cleaning properties like Motul. I personally use OEM ZF8 ATF, but the BMW performance shop I go to recommends Motul. Just an idea. If the 6th gear clutch pack is going, might as rebuild them all if that is the case. __________________ Car Stuff
	Appreciate 1 oczko9816.00 Quote

11-29-2022, 01:59 PM	#15
LA1Z24 Captain 356 Rep 764 Posts Drives: 2014 435i M Sport Join Date: Oct 2020 Location: Long Island iTrader: (0)	I had odd shifting issues running BM3 multimap. This is on a brand new, built PureDrivetrains transmission. Went to stage 2+ e30 and the issue is gone.
	Appreciate 1 oczko9816.00 Quote