M240i 6MT transmission whine

Sonertial · 06-26-2017, 11:19 AM

My 2017 EU M240i, 7000kms, developed a whine in 3rd gear after an evening of particularly hard driving. By hard I mean winding it out, and with the track itself ensuring that 3rd gear does the vast majority of the work, only one section where 4th gear is used, and all corners can be taken happily in 3rd, 2nd being a higher workload for an amateur.

The whine only occurs at around 1800-2300 rpm, only in 3rd and only when the throttle is lightly engaged. With foot off, or foot hard on, it's inaudible.

I talked to the local M tech, and he was sufficiently interested to want to have a look at it immediately. I was unable to leave the car in that particular day, but have a time booked after the summer holiday. As I heard it, he implied that there might be some concern about this gearbox/engine combination, it's the "old" transmission, but a new, torquey-er engine.

Is this gearbox the same as the M2 6MT? i.e the ZF S6-45 which if the info linked in this thread is correct, is only rated for 470NM, where the B58 is outputting 500+ across basically the whole rev range.

ZF website link

Any thoughts?

MarcoZandrini · 07-01-2017, 02:21 PM

I'd take it to the dealer. I highly doubt BMW would match the B58 engine with a tranny that can't handle the torque.

Sonertial · 09-19-2017, 01:14 PM

An update.

The dealer has replaced the transmission with a new one under warranty. The old one was packed off to Germany for analysis.

I'll just have to see how it goes. Hopefully the seeming lack of issues by others is a good sign.

XutvJet · 09-19-2017, 04:13 PM

It's my understanding that the M240, 340, and 440 uses the same, newer ZF 6MT as the M2. The M235 uses the "older" ZF 6MT that was used in 1M, and the 2014+ 335 and 435. The only differences being upgrades to the syncros and a beefier clutch. Overall, the ZF 6MTs are quite beefy, though they had their issues with syncros. A few magazines noted grinding on the 1-2 in their M2 test cars so that means the new ZF is subject to the same potential, though rare, syncro issues that have affected the ZF 6MT since the later 2000s.

06-26-2017, 11:19 AM	#1
Sonertial Private 47 Rep 61 Posts Drives: M240i 6MT Join Date: Oct 2016 Location: Stockholm iTrader: (0)	M240i 6MT transmission whine My 2017 EU M240i, 7000kms, developed a whine in 3rd gear after an evening of particularly hard driving. By hard I mean winding it out, and with the track itself ensuring that 3rd gear does the vast majority of the work, only one section where 4th gear is used, and all corners can be taken happily in 3rd, 2nd being a higher workload for an amateur. The whine only occurs at around 1800-2300 rpm, only in 3rd and only when the throttle is lightly engaged. With foot off, or foot hard on, it's inaudible. I talked to the local M tech, and he was sufficiently interested to want to have a look at it immediately. I was unable to leave the car in that particular day, but have a time booked after the summer holiday. As I heard it, he implied that there might be some concern about this gearbox/engine combination, it's the "old" transmission, but a new, torquey-er engine. Is this gearbox the same as the M2 6MT? i.e the ZF S6-45 which if the info linked in this thread is correct, is only rated for 470NM, where the B58 is outputting 500+ across basically the whole rev range. ZF website link Any thoughts?
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07-01-2017, 02:21 PM	#2
MarcoZandrini Major 444 Rep 1,264 Posts Drives: 2018 M240i Join Date: Jun 2017 Location: Virginia iTrader: (0)	I'd take it to the dealer. I highly doubt BMW would match the B58 engine with a tranny that can't handle the torque.
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09-19-2017, 01:14 PM	#3
Sonertial Private 47 Rep 61 Posts Drives: M240i 6MT Join Date: Oct 2016 Location: Stockholm iTrader: (0)	An update. The dealer has replaced the transmission with a new one under warranty. The old one was packed off to Germany for analysis. I'll just have to see how it goes. Hopefully the seeming lack of issues by others is a good sign.
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09-19-2017, 04:13 PM	#4
XutvJet Major General 5551 Rep 5,369 Posts Drives: 2011 Cayman Base, 2016 M235 Join Date: Mar 2016 Location: Kansas City iTrader: (-1)	It's my understanding that the M240, 340, and 440 uses the same, newer ZF 6MT as the M2. The M235 uses the "older" ZF 6MT that was used in 1M, and the 2014+ 335 and 435. The only differences being upgrades to the syncros and a beefier clutch. Overall, the ZF 6MTs are quite beefy, though they had their issues with syncros. A few magazines noted grinding on the 1-2 in their M2 test cars so that means the new ZF is subject to the same potential, though rare, syncro issues that have affected the ZF 6MT since the later 2000s.
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