[Kaps335i]

I have a 2013 335i xDrive with what I believe was a bad second gear synchro that required the trans to be replaced at 24k miles.

I admit I am used to Tremec transmissions and tend to be a little rough. I guess that is not OK with these manuals?

[akgambino]

Originally Posted by Kaps335i

I have a 2013 335i xDrive with what I believe was a bad second gear synchro that required the trans to be replaced at 24k miles.

I admit I am used to Tremec transmissions and tend to be a little rough. I guess that is not OK with these manuals?

What were the symptoms of the bad synchro?

Pretty cryptic post op lol! Any more details?

[Kaps335i]

Originally Posted by akgambino

What were the symptoms of the bad synchro?

Pretty cryptic post op lol! Any more details?

Grinding when shifting into second. But it would only happen under full throttle.

[ceedawg]

Originally Posted by Kaps335i

Grinding when shifting into second. But it would only happen under full throttle.

were you doing a lot of power shifting or missed shifts or something?

[Kaps335i]

Originally Posted by ceedawg

were you doing a lot of power shifting or missed shifts or something?

Nope. Always lift throttle and fully engage clutch.

I was shifting very hard. Hence the Tremec reference. When I owed Camaros and especially the first to second shift, it was done very quickly and tires would generally break free.

Since this is an xDrive, those tires are not breaking free. I am guessing the transmission is taking the brunt of the shift.

You can beat the hell out of a Tremec all day and it doesn't care.

[Kaps335i]

I guess speed shifting would be the proper term.

[ceedawg]

Originally Posted by Kaps335i

I guess speed shifting would be the proper term.

Yes speedshifting correct!. Well good to know as I will be extra mindful on mines since I want to roadrace. Not interested in times just won't to blast her around and have fun.

Same thing happens to EVO/DSM trannies the syncros do not like speed shifting and the forks don't like clutch dumping. AWD mani issues under duress. Common less you go Automatic, less stress on the drivetrain even on an awd platform.

[azuritschwarz]

ouch that's too bad, at least you're getting it replaced! my 6MT has been flawless so far & im xDrive as well (25000 km / 15000 miles). i'm not super hard on her but definitely enjoy my spirited driving, who doesn't?!

on a side note, & i don't mean to thread jack, but have you tried the BMS Clutch Stop? i've been debating getting one myself, so I thought maybe that would be something you might have tried already. for $10 seems pretty harmless to try it i guess....

cheers

[Kaps335i]

Originally Posted by yeg440i

ouch that's too bad, at least you're getting it replaced! my 6MT has been flawless so far & im xDrive as well (25000 km / 15000 miles). i'm not super hard on her but definitely enjoy my spirited driving, who doesn't?!

on a side note, & i don't mean to thread jack, but have you tried the BMS Clutch Stop? i've been debating getting one myself, so I thought maybe that would be something you might have tried already. for $10 seems pretty harmless to try it i guess....

cheers

Interesting. Didn't know about that. I would be curious how it affects driving in traffic. Definitely don't want that to be anymore annoying.

[azuritschwarz]

the clutch stop just removes the dead space at the bottom of the pedal for quicker engagement. a lot of people praise it saying it made the clutch travel a lot more tolerable & made their technique a bit better. albeit, the extra clutch travel is not the root of your problem here. just some food for thought for you & i as it seems a fair number of people get the clutch stop.

[Kaps335i]

I get that, which sounds like it may be good. But in traffic, depending on how far your leg is extended, it could end up being more tiring. And I am in traffic every day to and from work.

[azuritschwarz]

Only one way to find out! I am also in traffic daily. Just ordered one for myself

best of luck with the next gearbox!

[Hansboost]

My second gear synchro is fucked also. Im not under warranty so just riding it out haha

I think its a big flaw with these 6mt trans in these cars

[XutvJet]

Originally Posted by Kaps335i

I have a 2013 335i xDrive with what I believe was a bad second gear synchro that required the trans to be replaced at 24k miles.

I admit I am used to Tremec transmissions and tend to be a little rough. I guess that is not OK with these manuals?

How long do you wait before beating on the car after a cold start? The tranny fluid in these cars is pretty thick and ideal for performance driving, but it takes a good 15 to 20 minutes of driving to get the fluid up to temp assuming a cold tranny. Not allowing the fluid to warm can greatly increase your chances of damaging a syncro, especially on a hard high rpm 1-2 shift. The fact that the car is AWD doesn't help things as it puts even more stress on the syncro since there's no wheel spin on the shift to spread the torque load on the shift.

Like I've told owners, unless you're at the strip going for the absolute best ET, I recommend not slam shifting the 1-2 and just enjoying the feel of the 6MT. On a race track, you're not slam shifting the gears. You're shifting fast for sure, but not drag racing shifting.

[nemith]

My 6mt was replaced around 20k as well. Rough shifiting into 1st and 2nd so probably a similar deal.

I was not slam shifting or beating it up while cold.

I am not out of warranty and I can feel resistance with gentle shifts already again.

[Hansboost]

Will any other 6mt tranny fit up to the rear main of our N55s? like say the E92 6MT?

[Eulogy32]

Same story for me. Bought a pre-owned 2014 335 xdrive that I had inspected by a BMW dealership. They told me it passed their "certified pre-owned checklist". I had the transmission replaced four weeks into my ownership due to the same issues reported above - bad 2nd gear synchro. Only had 21k miles but was luckily covered under factory warranty.

Good news is now I have a brand new transmission that started my journey to a full FBO build!

[Salty B.]

Whoa. My transmission was replaced under warranty last December for the same problem — bad 2nd gear synchro — at only 21,000 miles. New clutch and slave cylinder as well.

The replacement trans doesn't feel appreciably different but so far I haven't crunched the 1-2 shift. I don't slam-shift or otherwise abuse the trans. Car is RWD.

[Bmwman325]

Started having a seccond gear issue in my tranny as well around 30,000 miles. Occasionally stick won't want to go into second, had to pull extremely hard into the gear or go into another gear and then back into second. Complained to dealer about it twice, left the car with them for over a week when I had 48,000 miles, and they finally reproduced it and replaced under warranty

[Salty B.]

Let's all hope that the remanufactured transmission we most likely got under warranty replacement has a more robust 2nd-gear synchro than the original.