M235 jerky upshifts. Bad tune or transmission issue?

370_n55 · 05-23-2024, 02:19 AM

Had a nightmare repairs with my m235i. Went for stage 1 tune, then they noticed that there's a leaky transfer case. As the shop didn't work on transfer cases, they recommended other shop. I brought car to them, they fixed the issue, however when fitting transfer case back they cracked, AT case, then they fixed that. Now it all seemed fine, however I get jerkiness in shifts especially when I hold rpms right before and upshift in sport mode, I feel slight jerkiness. When it warms up, the shifts are buttery smooth. At first I thought it has something to do with transmission, but as far as I think, if there was something wrong with transmission the issue would persist no matter the temperature of the transmission.
Now I think the jerkiness comes from tuning, like there's some kind of ecu limitation.

Has anyone experienced these symptoms, should I just detune/retune my car or maybe the issue maybe actually more serious than that and my headache will continue?

MarcoZandrini · 05-23-2024, 08:22 AM

The first step in diagnosing a problem is to scan the various modules for codes.

inverse121 · 05-23-2024, 01:59 PM

Can you simply revert the tune and see if the problem subsides?

Shirazkhan · 05-23-2024, 02:04 PM

Listen to Marco.Or else you wasting your time and money.

370_n55 · 05-24-2024, 05:17 AM

Car doesn't throw any codes.
Honestly thinking about doing full maintenance this summer, including transmission, detuning and enjoying the car in it's stock form. As there was zero issues before I decided to tune it.

However, yesterday and today car drove like a dream.

MarcoZandrini · 05-24-2024, 08:43 AM

Quote:

Originally Posted by 370_n55

Car doesn't throw any codes.
Honestly thinking about doing full maintenance this summer, including transmission, detuning and enjoying the car in it's stock form. As there was zero issues before I decided to tune it.

However, yesterday and today car drove like a dream.

What did you use to scan the car?

370_n55 · 05-24-2024, 09:48 AM

BimmerLink

zoro2001 · 05-24-2024, 11:50 AM

Check your tranny fluid level.

370_n55 · 05-24-2024, 03:23 PM

The fluid level is fine, actually it was overfilled.

MarcoZandrini · 05-25-2024, 09:06 AM

Quote:

Originally Posted by 370_n55

The fluid level is fine, actually it was overfilled.

The transmission was made by ZF . These transmissions don't like to be overfilled. The fluid level is critical. Fix the fluid level and report back.

05-23-2024, 02:19 AM	#1
370_n55 New Member 0 Rep 6 Posts Drives: m235i Join Date: Oct 2023 Location: Lithuania iTrader: (0)	M235 jerky upshifts. Bad tune or transmission issue? Had a nightmare repairs with my m235i. Went for stage 1 tune, then they noticed that there's a leaky transfer case. As the shop didn't work on transfer cases, they recommended other shop. I brought car to them, they fixed the issue, however when fitting transfer case back they cracked, AT case, then they fixed that. Now it all seemed fine, however I get jerkiness in shifts especially when I hold rpms right before and upshift in sport mode, I feel slight jerkiness. When it warms up, the shifts are buttery smooth. At first I thought it has something to do with transmission, but as far as I think, if there was something wrong with transmission the issue would persist no matter the temperature of the transmission. Now I think the jerkiness comes from tuning, like there's some kind of ecu limitation. Has anyone experienced these symptoms, should I just detune/retune my car or maybe the issue maybe actually more serious than that and my headache will continue?
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05-23-2024, 08:22 AM	#2
MarcoZandrini Major 473 Rep 1,306 Posts Drives: 2018 M240i Join Date: Jun 2017 Location: Virginia iTrader: (0)	The first step in diagnosing a problem is to scan the various modules for codes.
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05-23-2024, 01:59 PM	#3
inverse121 Private 18 Rep 53 Posts Drives: 2016 M235ix Join Date: May 2024 Location: Central NY iTrader: (0)	Can you simply revert the tune and see if the problem subsides?
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05-23-2024, 02:04 PM	#4
Shirazkhan Second Lieutenant 56 Rep 200 Posts Drives: F22,GO1,i20,POLO,BANTAM,BREZZA Join Date: Jan 2021 Location: South africa iTrader: (0)	Listen to Marco.Or else you wasting your time and money.
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05-24-2024, 05:17 AM	#5
370_n55 New Member 0 Rep 6 Posts Drives: m235i Join Date: Oct 2023 Location: Lithuania iTrader: (0)	Car doesn't throw any codes. Honestly thinking about doing full maintenance this summer, including transmission, detuning and enjoying the car in it's stock form. As there was zero issues before I decided to tune it. However, yesterday and today car drove like a dream. Last edited by 370_n55; 05-24-2024 at 05:25 AM..
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05-24-2024, 09:48 AM	#7
370_n55 New Member 0 Rep 6 Posts Drives: m235i Join Date: Oct 2023 Location: Lithuania iTrader: (0)	BimmerLink
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05-24-2024, 11:50 AM	#8
zoro2001 Private 24 Rep 51 Posts Drives: 2014 M235i Join Date: Nov 2021 Location: WI iTrader: (0) Garage List 2014 BMW 235i [0.00]	Check your tranny fluid level.
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05-24-2024, 03:23 PM	#9
370_n55 New Member 0 Rep 6 Posts Drives: m235i Join Date: Oct 2023 Location: Lithuania iTrader: (0)	The fluid level is fine, actually it was overfilled.
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