2011 335ix Manual - Transmission

[afflannery]

The transmission started making whirring noises. Transfer case was checked, fluids replaced there and in transmission, but my mechanic's recommendation is to replace the transmission.
New is extremely hard, if not impossible, to find.
Used is just as expensive, and has unknown reliability.

All the rebuild shops in the area advocate to replace, not rebuild. So the questions are
1. Why not rebuild. I found a new rebuild kit on ebay for $370 or so.
2. Any idea where to go to get a new transmission?

Other thoughts,
Thanks!
Tony

[bmwdirtracer]

https://www.getbmwparts.com/oem-part...d9-23007599346

This is an online BMW dealership. Another such entity shows the part as no longer available....so maybe, maybe not.

https://www.car-part.com/
This is a link to dozens of salvage yards across the country; enter the car as a 335i, then choose the 6spd manual for AWD after that.

Now all that said, I personally would want to hear the car, on a lift, using a stethoscope, before condemning the transmission. The transfer case and front differential of this car are FAR more common failure items than this transmission.

[afflannery]

Thanks for the feedback.
The transfer case was the first suspected culprit, but it was not the source of the noise. I don't know if he used a stethoscope, but the noise is fairly significant. I feel like the mechanic diagnosing the transmission was "probably" accurate, but how to solve it short of replacing new was out of his comfort zone.

I really love this car and don't mind spending some money on it. This problem has just cropped up in the last 2 weeks.

So why not rebuild it?

[bmwdirtracer]

No reason not to rebuild it, if you can find someone to do it, AND whatever parts are worn or damaged.

BMW doesn't sell any of the parts which are likely bad, and an ebay $370 "rebuild kit" likely won't include all the gears and shafts and forks and bearings. So you're unlikely to be able to fix the actual problem, once it's found. And by then, your gearbox will be in pieces.... If you find a shop that's willing to do it, and manage to locate the parts they need to fix it, please check back and let us know.

EDIT: When does this "hum" happen? Accelerating? Decelerating? In a particular gear? "Humming" is not how gear sounds are usually described.

[MarcoZandrini]

Quick question: does the shop specialize in BMWs? If not, try www.bimrs.org to find a reputable indie shop that specializes in bimmers. San Diego has quite a few of these shops.

[afflannery]

The shop that diagnosed that the sound was coming from the transmission does specialize in BMW's. This was just above their ability to tackle and I give them credit for not trying.

The sound it makes is not a humming, but a whiring. The pitch changes with speed of the car (not RPM's), and it gets a little louder when accelerating or decelerating - under load. It's not obnoxious or grinding. Definitely not tire related, and the transfer case was looked at, but it is definitely the transmission. Feedback I have received is that this is a rare occurrence.

I'm about to engage with ... dare I say it ... the dealer. This car is NOT that old.

[JohnelP]

Do the following tests and tell us what happens (noise, no noise, noise up or down):
1) with the car still stopped, put it in neutral, with clutch dis-engaged. Needless to say, emergency brake on + brake pedal pressed.
2)Have the car stopped. With it still in neutral, release the clutch to engage
3) while driving at low speed (and obviously following all safety protocols), with the transmission still "in gear" depress the clutch to dis-engage. Leave it with gear coupled, just with clutch pressed, car rolling
4) while driving at low speed (and obviously following all safety protocols), put the car in neutral and release the clutch to have engine engaged with transmission, but in neutral, car rolling


I assume the noise is present when driving in all gears, not just one.


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you are wasting time with dealer. I saw one person on the forum that had a manual transmission rebuilt by a racing transmission shop in california. it was a GS6- 53BZ, not a 45 like yours, but they are pretty close. These transmissions are very difficult to rebuild due to interference press technology, but some shops can do it. Many shops claim they can, but only a handful of shops can really deliver