SMFW chatter

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Bmwfixerguy1

Lieutenant
Jun 5, 2017
822
So when switching to a single mass flywheel you tend to get a lot of gear chatter. Some can just bump the idle a bit wit mhd while others have found some concotions of gear oils that have quieted the the chatter a great bit.

What gear oil mix are you using???
 
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Bmwfixerguy1

Lieutenant
Jun 5, 2017
822
900rpm & https://www.ecstuning.com/b-redline-parts/mtl-manual-transmission-fluid-75w80-1-quart/rl-space-mtl/ has my car w/ tolerable chatter... 950rpm would probably get rid of it, but I'm trying to keep idle as low as possible. Thoughts on idle rpm?
Really thats what you runcfir mtf? Thats a little unorthodox for out trans. Most guys real the D4 or D6. Have you tried either of those? They are much thinner but shift like a dream! May not be best for chatter though, did you choose that oil for chatter relief specifically?
 
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camberadam

Sergeant
Feb 15, 2017
257
Baltimore
Really thats what you runcfir mtf? Thats a little unorthodox for out trans. Most guys real the D4 or D6. Have you tried either of those? They are much thinner but shift like a dream! May not be best for chatter though, did you choose that oil for chatter relief specifically?
Honestly... It's as simple as I have a manual transmission, so I run manual trans fluid. To me, using ATF in a manual sounds unorthodox if anything. I haven't tried D4 or D6. I ran Redline 75w90 for approx 30k miles w/o issue; the 80 is new so I figured I'd try it. The 80 does feel smoother than 90, but wouldn't mind improving further either.
 

Bnks334

Sergeant
Dec 1, 2016
402
New York
Honestly... It's as simple as I have a manual transmission, so I run manual trans fluid. To me, using ATF in a manual sounds unorthodox if anything. I haven't tried D4 or D6. I ran Redline 75w90 for approx 30k miles w/o issue; the 80 is new so I figured I'd try it. The 80 does feel smoother than 90, but wouldn't mind improving further either.
Don't try to dampen noise by using a fluid that is thicker than what the low friction synchros require. It will effect shifting even if you've convinced yourself it doesn't. BMW engineers know a thing or two more than you and they specifically state not to use any friction modifiers in the box, which is why atf is used.

Use Rheingold to get your idle up to at least 830 (let's you bump it up 150 rpms max). Ideally, I'd like 900-1000, but n55 doesn't have the tables defined yet.
 
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camberadam

Sergeant
Feb 15, 2017
257
Baltimore
Gs6-53 should get d6 and gs6-45 should get d4. Dont try to dampen noise by using a fluid 300% thicker than what the low friction synchros require. It will effect shifting even if you've convinced yourself it doesnt. BMW engineers know a thing or two more than you and they specifically state not to use any friction modifiers in the box, which is why atf is used.

Use Rheingold to get your idle up to at least 830 (let's you bump it up 150 rpms max). Ideally I'd like 900-1000, but n55 doesn't have the tables defined yet.
Not sure why you're quoting me... None of this applies to anything I've done.
 

Bnks334

Sergeant
Dec 1, 2016
402
New York
Not sure why you're quoting me... None of this applies to anything I've done.
I quoted you because using an atf (the fluid that best matches zf's recommended fluid) in a 6mt seems "unorthodox" to you and you instead run significantly thicker mt fluids (not recommended).
 

Bnks334

Sergeant
Dec 1, 2016
402
New York
You still seem confused. Let me draw you a picture...
spoolstreet_idiot_zpskhjy23ot.jpg
Lmao yeah... I get all my fluid recommendations from ecs too. They are engineers and they are never wrong in how they categorize products! /sarcasm

Fyi, OE BMW fluid is a mtf lt-5 fluid (transmission itself is stamped with old MTF LT-3 label) MTF LT-3 has a kinematic viscosity of 6.1cst at 100c. ZF recommends pentosin ffl-3 (7cst at 100c) as a replacement. That is also why D4/D6 are recommended fluids (7.5/6.4 cst). The redline MTL (10.4cst), 75-80 (10.4cst), and 75-90 (15.6cst) are not. They are significantly thicker fluids that are NOT meant for use in later generations of zf gearboxes. Need me to draw a picture for you?
 
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camberadam

Sergeant
Feb 15, 2017
257
Baltimore
Lmao yeah... I get all my fluid recommendations from ecs too. They are engineers and they are never wrong in how they categorize products! /sarcasm

Fyi, OE BMW fluid is actually pentosin ffl-3 which has a kinematic viscosity of 7cst at 100c. That is why d4/d6 are recommended fluids (6.4/6.6 cst) and mtl/75-85/90 with 15cst-20cst are not. They are significantly thicker fluids that are NOT meant for newer generations of zf gearboxes. Need me to draw a picture for you?
OMG I think I just heard my transmission grenade. Maybe it was that grease I put on my pilot bearing... :rolleyes:

<unwatch>
 

Bnks334

Sergeant
Dec 1, 2016
402
New York
OMG I think I just heard my transmission grenade. Maybe it was that grease I put on my pilot bearing... :rolleyes:

<unwatch>
Ok, get proven wrong then reply again with another comment that makes you sound even more ignorant...

BMW (actual engineers) is 100% accurate in saying the pilot bearing should NOT be greased and Tony is 100% wrong in saying that it should be. Please Google oilite bearings. You do not grease these types of bearings and if you do put synthetic grease on your pilot bearing all you will be doing is increasing friction and decreasing the life of the bearing.

Please save the ricer engineering for elsewhere.
 
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camberadam

Sergeant
Feb 15, 2017
257
Baltimore
Ok, get proven wrong then reply again with another comment that makes you sound even more ignorant...

BMW (actual engineers) is 100% accurate in saying the pilot bearing should NOT be greased and Tony is 100% wrong in saying that it should be. Please Google oilite bearings. You do not grease these types of bearings and if you do put synthetic grease on your pilot bearing all you will be doing is increasing friction and decreasing the life of the bearing.

Please save the ricer engineering for elsewhere.
The same engineers that designed our wonderful valve covers & pcv systems... You want to treat your car like it can fly you to the moon have at it. I'll take my ricer engineering that's kept several of my cars running like a top for 200k+ miles.
 

Bmwfixerguy1

Lieutenant
Jun 5, 2017
822
Holy cow this got outta hand quick lmao

So you know Adam my original reply like 20 replies ago wasn't melicious at all!
Just asking if you ran the redline mtf for chatter reasons as a specific choice. I'm pretty sure guys make a cocktail with d6 and mtf

Bottom line Yea Yea I get it with zf engineers and I've dealt with them for almost 2 decades now on first name basis relationships.
They are all dramatic to say the least lol
I understand what a box calls for but use what works for you situation end of story!
 
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Itsbrokeagain

Corporal
Jan 28, 2018
174
Strong Island
I have yet to hear any kind of oil concoction reducing gear chatter and Ive been messing around with BMWs for the better part of 17 years. The biggest improvement? Kick idle to 900 or 1000. Will eliminate most of it. Having the AC on is going to make the noise consistent.

I dont get why people complain about the noise. Who gives two shits about what other people think when youre driving?

"hey your cars rattling!"
"got it, thanks"

If friends/girlfriend/parents/society says your car sounds like a box of rocks, then kindly inform them that I will switch back to a DMFW, if they are so generous as to pay the bill for parts and labor.
 
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Reaper0995

Specialist
Jan 10, 2017
69
I dont get why people complain about the noise. Who gives two shits about what other people think when youre driving?
Actually I'm the one who is annoyed, I can somewhat change my driving for when others are in the car but the drone at 1500-1900 rims when I apply any throttle is very annoying. It's a nice relaxing smooth car but now the clutch does make it a bit more harsh than I care for.

I wouldn't mind paying for an upgrade that could eliminate this either, but given that there are no alternatives besides run less power, there really isn't any choice.

I still ave stock fluid in my transmission, but will be switching to d4 soon along with the bigger turbos. I'll report back if it makes a difference.
 

Itsbrokeagain

Corporal
Jan 28, 2018
174
Strong Island
Actually I'm the one who is annoyed, I can somewhat change my driving for when others are in the car but the drone at 1500-1900 rims when I apply any throttle is very annoying. It's a nice relaxing smooth car but now the clutch does make it a bit more harsh than I care for.

I wouldn't mind paying for an upgrade that could eliminate this either, but given that there are no alternatives besides run less power, there really isn't any choice.

I still ave stock fluid in my transmission, but will be switching to d4 soon along with the bigger turbos. I'll report back if it makes a difference.
d4 will most likely not make a noise difference, but will improve shifting. What other mods do you have? solid diff mounts? stiffer subframe bushings? AKG engine mounts? Any of these parts will work in harmony with a single mass flywheel and add a resonance. On a car with nothing more than IS mounts, new rubber trans bushings and M3 subframe bushings, there is no extra drone at 1500-1900. The exhaust on the car is loud as it is, so any resonance that is there (if any) will not even be felt or heard.
 

Reaper0995

Specialist
Jan 10, 2017
69
Yeah I don't think it will improve the noise but its definitely due for a change, either way I'll report that info but not anticipating much on that end.

For mods I'm FBO with a spec 3+ and smfw. I have GC turbos to install soon but not yet in the car. Still stock motor and transmission mounts, and I'm xi if that's matters.

I had started a thread a while ago but didn't really find a direct answer... I had asked why is it that older cars were made for for decades without a dmfw and they sounded just fine, but a lot of new cars have them and removing them sounds terrible. Just at a fundamental level, what is so different from the new cars that makes them different? Engines and transmissions are basically the same, there's nothing truly that different from old to new that would affect noise.
 

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