[DanielBimmer]

Anyone else's f30 335 m sport whine when reversing? I thought they were all like that

[Monstr6]

Mine does the same thing, I just noticed last night

[claykin]

Every F30 335 I've driven with the 8AT has some level of whine while backing up.

[fecurtis]

That's because in a lot of cars, they use straight cut gears for reverse and helical for the forward gears. The straight cut gears produce a whine sound that's more noticeable the faster you're going.

It's normal.

[smv]

Mine developed a more pronounced noise lately, more like a police car siren. If in a closed garage it is really noticeable, very straight siren sound, pitching up in frequency as reverse speed increases. Not a whining/gear sound. SA on dealer tried to convince me it is normal, but it was noticeable even in open space with windows closed. I told him I did not buy a police car and certainly after 7 BMWs I can tell what is normal and what not. End of story! He made a note to review the whole thing in the next soon to come service. (25Kkms)

[Golden Arrow]

Originally Posted by fecurtis

That's because in a lot of cars, they use straight cut gears for reverse and helical for the forward gears. The straight cut gears produce a whine sound that's more noticeable the faster you're going.

It's normal.

+1

Is this at higher reverse speeds, OP? If so, my suggestion is to reverse slower, which is also safer. Every car I've owned from varying manufacturers (Nissan, BMW, Chevy, and Mercedes) have made some sort of noise when in reverse, which is due to the gearing.

[FC4]

Yeah, mine whines while in reverse at speeds above 15 MPH. Totally normal.

[Professor///M]

Originally Posted by fecurtis

That's because in a lot of cars, they use straight cut gears for reverse and helical for the forward gears. The straight cut gears produce a whine sound that's more noticeable the faster you're going.

It's normal.

I've read this multiple times. Mine is loud, and noticeable out of any of the other 5 BMWs I've owned.

[Golden Arrow]

Originally Posted by JSTDR1V

I've read this multiple times. Mine is loud, and noticeable out of any of the other 5 BMWs I've owned.

Hmmm. Have any of your other cars had the ZF 8-speed automatic gearbox?

You haven't answered the question: How fast are you traveling in reverse when this "loud and noticeable" sound occurs?

[Professor///M]

Nope, all have been the 6 speed auto. How fast, as fast as the car goes without pushing the gas, but with your foot off the brake out of the garage! It's all the time.

Sorry, didn't realize there was a question.

[DanielBimmer]

Originally Posted by Golden Arrow

Hmmm. Have any of your other cars had the ZF 8-speed automatic gearbox?

You haven't answered the question: How fast are you traveling in reverse when this "loud and noticeable" sound occurs?

As soon as I start reversing. Gets louder as speed increases

[Golden Arrow]

Originally Posted by JSTDR1V

Nope, all have been the 6 speed auto. How fast, as fast as the car goes without pushing the gas, but with your foot off the brake out of the garage! It's all the time.

Sorry, didn't realize there was a question.

No worries.

If you're off-throttle and hearing the whine, that's definitely odd. The whine should be directly related to the reverse speed. Higher speed= more whine. If it's moderately loud when you're barely moving in reverse, that definitely warrants a phone call to your service advisor.

[FC4]

Originally Posted by DanielBimmer

As soon as I start reversing. Gets louder as speed increases

Yep. I just hit 35 MPH in reverse. Very pronounced whine.

[oceanview]

I wanted to hang on again on this.
I've just read in a German BMW Forum, that the wining in reverse was caused due to a bad transmission series. BMW changed the whole transmission on that specific car. (His post was dated 09/13 so quite new)

I just wonder, if there is anyone who has NO wining in reverse with a ZF 8AT? (Maybe on newer F3x models produced in 2014/2015.)
I can already hear the wining at very low reverse driving speed (i.e. 2 mph).

I guess when taking to the Dealer they will say it's as designed. But if there other N55 ZF8AT, which are not wining in reverse it would be another story.

[Vitoco]

Originally Posted by oceanview

I wanted to hang on again on this.
I've just read in a German BMW Forum, that the wining in reverse was caused due to a bad transmission series. BMW changed the whole transmission on that specific car. (His post was dated 09/13 so quite new)

I just wonder, if there is anyone who has NO wining in reverse with a ZF 8AT? (Maybe on newer F3x models produced in 2014/2015.)
I can already hear the wining at very low reverse driving speed (i.e. 2 mph).

I guess when taking to the Dealer they will say it's as designed. But if there other N55 ZF8AT, which are not wining in reverse it would be another story.

Sicher nüt? Tell me more please,when was the bad transmission series made? Mine was produced 09/12

[stxf30]

Originally Posted by Vitoco

Sicher nüt? Tell me more please,when was the bad transmission series made? Mine was produced 09/12

9/12 here too. No whining in reverse.

[Tiago@VRSF]

Originally Posted by fecurtis

That's because in a lot of cars, they use straight cut gears for reverse and helical for the forward gears. The straight cut gears produce a whine sound that's more noticeable the faster you're going.

It's normal.

This

[TANG2864]

whining in reverse happens in a lot of cars. I happen to only usually hear it windows down, quiet environments though on my previous cars, and current vehicles. I have a 2015 435i and when i back up or anything slowly, there is not a noticeable whine, only one time when i reversed at about 10-15+ mph did i notice a whine, like any other car. normal backing out of garage or parking spots has no whine.

[oceanview]

Thanks for the info TANG2864
I can hear the whine even with very low reverse speed. Will head to the dealer and ask if this is a known problem.

It's clear to me, that straight cut reverse gears usually are the reason for the noise. But as I heard different stories now about the F3x reverse driving noise, I really want to find out.

[oceanview]

I catch this case up again after seeing the ZF Service location and talking to the Service Manager yesterday.

The whining in reverse can happen to all the early production 8HP models (not only the F3x Series). Built before 2014 or so.

The whining is caused by the 3rd wheel set in the transmission.
The three planetoid wheels of the 3rd wheel set are bedded on round washers, which divide the planetoid wheels from the aluminum frame where the wheels are mounted.
These round washers are causing the whining!
The round washers can/will also work themselves into the aluminum frame over the time, causing a even louder whining and possibly causing also a sudden complete transmission malfunction.

ZF has actually fixed this in the production, by using oval washers instead of round washers.

Solution:
The Service Manager told me, that they can repair the "whining" transmissions using parts of the later produced 8HP with oval washers (and some other parts)
He also told me that an exchange with a refurbished transmission of the same type will possibly not solve the whining, because the refurbished transmissions will normally also get the round washers.
The fix, using parts of a later production series for a early production series transmission is a hack of this Service Center.
It will not be applied by ZF refurbishing center.

Cost for the repair around € 4'000.- (Euros)

At least the cause of the whining is clear to me now.
It's actually "normal" because it's the way of how the unit was designed.
But it's a poor design, which ZF recognized and re-designed.

[obeeone]

Just to add some information my car is a 2015 manufactured October 2014 and I have zero whining noise while in reverse. They must have fixed something if the earlier models have a pronounced whine, because I reverse into my garage everyday and my driveway is about 100 feet long. I have never heard even the slightest whining noise now at 42k miles.