Manual Transmission discussion

[BMW665]

I'd like to hear from those that decided to go with a manual transmission . I have a few questions

Have you made any mod's that increase the performance or smoothness of shifting?

BMW has added a restrictor to the hydraulic system that requires you to slow your shifting down. What is the benefit?.

At a stop light do you feel shifting to 1st is easy? I have driven other BMW 335i's and all seem to be about the same. A little sluggish at first until everything is warmed up then ok after that

Any maintenance that have benefited your shifting?

[RobC2]

My Z4 is a manual and I still have the clutch delay valve in place. I will admit it took a bit of driving to get used to the clutch release, but I am very smooth with it now. I have had no issues with the gearbox, it seems very smooth and positive. I have only owned the car since late August. It is not driven every day and it hasn't really been cold yet. I have owned numerous manual transmission cars, but this is my first BMW and I am quite pleased with my transmission choice.

[jparnes1]

I have a 2012 with 6MT, 31K miles. I think if you can't shift this tranny well, give it up. Very smooth (but a little notchy when it's cold, like most MT's) and I'm not sure what you mean but I can shift pretty damn fast. I'd like the clutch pedal to have less travel, but it's no biggie. My previous Z4 had DCT. This is way more fun. All in all, very happy. Too bad you can only get it in the 28i now.

[BMW665]

Notchy is a good way to describe the feel. where I notice the slowness is shifting from 1st to 2nd. a slower shift seems to be a smoother in gear shift .

What is the purpose of the Shift delay?

[BMW665]

The clutch delay valve only works on disengage not the speed in shifting

[bigendbob]

I removed the CDV which reduced judder on take up when cold.
I replaced a quart of the gearbox oil with Redline D4 ATF.
Has made the changing of gears a little smoother.
Now wondering whether to go the whole hog and change it all to D4 or D6 with winter approaching.

http://www.redlineoil.com/application.aspx

[jparnes1]

Originally Posted by BMW665

The clutch delay valve only works on disengage not the speed in shifting

Sorry, you've got that backwards. The CDV is a fluid restrictor built in line between the hydraulic line and the clutch slave cylinder. It acts to minimize rapid engagement of the clutch (as in dumping the clutch at 6000 rpm) and thereby avoiding harmful effects to other parts of the drivetrain. Why is it there? Because BMW is on the hook for your drivetrain for the first 4 years.

[jparnes1]

Originally Posted by bigendbob

I removed the CDV which reduced judder on take up when cold.
I replaced a quart of the gearbox oil with Redline D4 ATF.
Has made the changing of gears a little smoother.
Now wondering whether to go the whole hog and change it all to D4 or D6 with winter approaching.

http://www.redlineoil.com/application.aspx

Bigendbob, did you notice juddering in all gears? I'm finding it only in first gear for about 5 minutes until the fluid gets a little warmer. If that's due to the CDV, I'm taking it out. BTW I use D4 ATF too - good stuff.

[bigendbob]

Only in first.
First couple of minutes in the morning.
Also i now always put the car into sport mode so throttle responds better.
Ordered D6 so that will go in shortly.

When i test drove the car i said to the salesperson "typical notchy BMW gearbox".
They once lent me a new Series 1 diesel, that was smooth as silk, so they can make nice gearboxes, just not the Zed!

When changing gear i ride the throttle slightly as it seems to change gear smoother as though the gearbox doesn't like to come off load when changing gears.

Its hard to tell if the notchy-ness is due to the syncro meshing or the shaft connected to the gear lever is held by spring loaded pins, which seem overly loaded. Maybe to hold it in gear.

[jparnes1]

Originally Posted by bigendbob

Only in first.
First couple of minutes in the morning.
Also i now always put the car into sport mode so throttle responds better.
Ordered D6 so that will go in shortly.

When i test drove the car i said to the salesperson "typical notchy BMW gearbox".
They once lent me a new Series 1 diesel, that was smooth as silk, so they can make nice gearboxes, just not the Zed!

When changing gear i ride the throttle slightly as it seems to change gear smoother as though the gearbox doesn't like to come off load when changing gears.

Its hard to tell if the notchy-ness is due to the syncro meshing or the shaft connected to the gear lever is held by spring loaded pins, which seem overly loaded. Maybe to hold it in gear.

Aside from the lack of juddering, have you noticed any other changes after your deleted the CDV? Quality of shifting, the way you work the clutch, etc..?
I also give it just a little gas when upshifting.

[vasmir]

I had a 2012 6-spd for two years before selling.

I wasn't a huge fan of the gearbox. It was too notchy/mechanical, and not nearly as smooth as I was expecting or would have liked. Yes it was worse when cold out - but even when warm shifting down to 1st at a stop light, or into 2nd after rolling, was unpleasant in my opinion. Just too notchy and decidedly un-smooth.

Also, occasionally the car wouldn't allow me to shift into reverse from a dead stop. It was pretty rare, but I'd have to let the car roll slightly before the syncro would mesh.

The clutch delay valve was there and took some getting used to - but I didn't feel as if it slowed my shifting down during spirited driving. I didn't notice it at all during autocross sessions. No biggie.

Gearbox feel/action was part of my decision to sell. The shifting in every other BMW I've driven (my old Z3, 1 series, 2 series, older gen M3, etc) was far superior.

[bigendbob]

http://www.zf.com/media/media/img_1/...iebe-S6_zf.jpg
Thought this was a nice pic of similiar gearbox.
And dual clutch.
http://www.zf.com/media/media/img_1/...-7DT-45_zf.jpg

[BMW665]

excellent pic's thanks for posting. Notchy shifting seems like something we all have to live with. when I started with the post, I was hoping to find someone that has figured out how to change the notchyness to a smooth shift from 1st to 2nd mostly. skip shifting works fine along with feathering the gas a bit as you shift. I switched to royal purple as well.