F40 MU9 transaxle, finally getting around to playing with this one. I have a brand new GM G6 clutch, which is a solid disc, as it is intended for the dual mass flywheel, and would like to use it - spline engagement is good, and the fingers match the throwout bearing better than the Fiero clutch. Given that, I have two choices for the flywheel:
One is to use the stock dual mass flywheel - to the best of my searching, the 3900 crank butt is the same as the other 60 degree V6 engines (this one is going behind a 3.4 TDC). Unless anyone knows better, should just bolt up with the only worry being the total HTOB travel. Available online for $360.00 brand new.
The other is to make up a solid flywheel - no worries for me, I have material and the machinery. I can't use the "normal" Camaro flywheel, G6 clutch is 9 1/2" diameter, and uses a stepped flywheel. Only concern is noise/vibration, running a solid disc with a solid flywheel. This is pretty well 100% street use, stock crate DOHC, not worried about power handling ability, just driveability. My understanding is that the clutch disk springs do nothing for the engagement characteristics, this is determined only by the friction materials (flywheel, disc, pressure plate) and the "Marcel" or built in waviness of the clutch disc. Not worried about that to much. My best understanding is that the springs come into play at idle, and at low rpm/higher torque loading, helping to absorb power impulses in this range. The ongoing switch to dual mass flywheels by manufacturers is a result of the enhanced torque range of modern engines, giving drivers the ability to "lug" engines down to the 12-1500 rpm range. Not really worried to much on this score either, not my driving style, neither is it well suited to the TDC. This car is a play car, not a daily driver. That leaves the idle range to worry about, in my mind at least.
Anybody tried either one of these? I have heard the horror stories on dual mass flywheel failures, but tend to think that it is because the engines were lugged excessively, making the flywheel work harder. On the other hand, I have heard the transmission noise complaints also. Supposedly, the MU9 (2007) transmissions were better in that respect, but not sure why. And finally, I am aware that dual mass flywheels are "tuned" to engine/flywheel combinations, I have NO idea how an engine change would affect this - I assume minimally, still a V6, close to the same capacity, but not sure if the lack of low speed torque would affect it. I would not expect the difference in rotating mass to affect it at all.
I will watch this closely. I have the same engine with a Getrag 5-speed and an F40 in the wings. I've spent a couple of evenings at the computer trying to work out how I will do the flywheel, but nothing jumps out as "the way to go". I would just go with the stock dual mass unit, but that sucker is heavy! 25 pounds, IIRC. I have a Fidenza aluminum flywheel on it now and I like the throttle response. I don't know if there's any option to get some weight out of the stocker.
I think I would go with a flywheel type that is normal to the engine/transmission being used. Really I think I would go with a plain jane flywheel no matter what engine I was using just to keep things simple. As for the spring center disc, once it is engauged I don't think you will notice any difference at all. Larry
I would worry less about the HTOB travel, and more about whether the dual mass flywheel has the correct balancing for the LQ1. The F40 bell housing is deeper than the Getrag and Isuzu transmissions that came in the Fiero, as it's designed to be used with the dual mass flywheel, and the clutch, that's in the G6.
If the balance is correct, then using the dual mass flywheel from a 3.9 should be no problem on the 3.4. Without it, you will need to space the clutch friction surface out anyway, so that the HTOB can properly engage the pressure plate.
Sprung hub clutches and dual mass flywheels in BMW's are used PURELY and ONLY for reduction of gear rattle in the transmission at idle. That is all. People run solid hub disks with single mass flywheels all the time and don't have problems.
I have not heard a rational explanation of why things should be different with the F40, although there are people who will tell you they are.
I have an solid aluminum flywheel and run a Spec Stage 4+ 10" clutch with my LS4/F40 combo. No springs what so ever. My engine has a lopey camshaft, so at idle with the trans in neutral and clutch pedal released I can hear a rocking noise from the gears within the transmission because the input shaft rpm isn't steady. It is worse the faster I release the clutch and I can make it less by slowly releasing the clutch at idle, and eliminate it entirely by just keeping the clutch pressed. While I don't particulaly care for the rattle noise, I like everything else about the transmission and I really doubt the springs would make much of a difference when I don't have a stead idle speed (+/- 75 rpm fluctuation)
[This message has been edited by fieroguru (edited 07-11-2013).]
You may just be able to use a Camero flywheel without turning it down for proper spacing. Simple is good. Larry
The camaro ring gear is 148 tooth and will not fit within the bellhousing. You would have to turn the ring gear landing down further to accept the 142 tooth ring gear, but then you are left with about 1/8" of material holding the ring gear. It has been done before, but it isn't just a bolt in and go type option.
Camaro (3.1) flywheel is a no go with the G6 clutch - not enough meat to cut the required step into it, and still have the friction surface in the same location.
Good point on the balance of the dual mass flywheel - I had assumed that the 3900 used a neutral flywheel, but had not checked to see. The weight is not so much of a concern to me - I do like an aluminum flywheel for "spirited" driving, but truth is on the street, I'm hard put to remember the last time I even used full throttle. It's nice sometimes to be able to idle away from a stop sign.
Kinda figured idle noise would be the biggest problem, Will. Fieroguru, is it more of an annoyance to you, like you hear it, but your average passenger would not notice, or is it the kind of thing that every pedestrian on a crowded street turns to see what is wrong with the car?
My search had shown that all 60 degree V6's shared a common crank butt pilot, bolt pattern and location - can anyone confirm?
Originally posted by fast40driver: I do like an aluminum flywheel for "spirited" driving, but truth is on the street, I'm hard put to remember the last time I even used full throttle. It's nice sometimes to be able to idle away from a stop sign.
Buy a Honda. No low end power at all. Full throttle all day long!
As for the crank flange on 60 degree V6s, for the pushrod engines, they should all be the same, yes. The new High Feature DOHC engines are 60 degree blocks, but are a completely different beast from the standard pushrod engines.
Originally posted by fast40driver: Kinda figured idle noise would be the biggest problem, Will.
I have a sprung hub SPEC Stage 3 with my Getrag and still have input bearing noise idling in neutral with my foot off the clutch. Sprung hub is not a panacea.
1990 Camaro 3.1 Flywheel: Part Number: FW2728 Weight: 18.97 lbs Warranty: 1 YR Crankshaft Bolt Hole Count: 6 Dual Mass Flywheel: No Flywheel Diameter (in): 12.429 Flywheel Material: Steel Flywheel Weight (lbs): 18.97 Flywheel/Flexplate Tooth Count: 148 Item Grade: Standard Replacement Package Contents: Flywheel
Joseph Upson and Fierobsessed have both used this flywheel with the F40 and both of them removed the 148 ring gear and modified the flywheel for the 142.
Fieroguru, is it more of an annoyance to you, like you hear it, but your average passenger would not notice, or is it the kind of thing that every pedestrian on a crowded street turns to see what is wrong with the car?
I will take a video/sound slip when I get home. On the F40 with my camshaft, it is very noticeable and sounds like a rod knock. It goes away by pushing the clutch and can be minimized or exaggerated by the speed at which the clutch is released. I tend to keep my foot on the clutch to keep it quiet.
Pushing in the clutch also end loads the crank and flywheel, are you sure you don't have some other problem going on? Even a loose flywheel? Larry
It's the tranny and if I recall correctly it's applying the clutch with the tranny in gear that helps quiet it down, otherwise without the dualmass it will make a lot of racket that seems to be idle rpm regulated. Higher idle rpm makes it much better.
Pushing in the clutch also end loads the crank and flywheel, are you sure you don't have some other problem going on? Even a loose flywheel? Larry
The idle rattle is a pretty well know "issue" with the 2006 F40 and likely one of the reasons you can buy a "zero mile" 2006 unit for $550 shipped to your door. Mine was a zero mile unit and the rattle has been present since startup about 3K miles ago. If it was the flywheel being loose, it would also rock as you blip/release the throttle or at every downshift/upshft and that doesn't happen. I also think the frequency of the rattle is too quick for a 28lb flywheel/clutch/pressure plate combo to do w/o a lot more force or vibration.
The rattle frequency would be three times the RPM or one each power pulse. Larry
I think it really depends on exactly how the rattling sound is being made. If the sound is something coming back into contact with something spinning with the input shaft after an ignition pulse bounced it away, then yes 1 sound event per ignition pulse (my car is a V8). However, if it is bouncing forward on an ignition pulse, then hitting the backside of something else before the "hit" from the 2nd ignition pulse then you could hear 2 sound events per ignition pulse.
Originally posted by fieroguru: The idle rattle is a pretty well know "issue" with the 2006 F40 and likely one of the reasons you can buy a "zero mile" 2006 unit for $550 shipped to your door. Mine was a zero mile unit and the rattle has been present since startup about 3K miles ago. If it was the flywheel being loose, it would also rock as you blip/release the throttle or at every downshift/upshft and that doesn't happen. I also think the frequency of the rattle is too quick for a 28lb flywheel/clutch/pressure plate combo to do w/o a lot more force or vibration.
Which fluid are you running in your trans? I've seen reports on some forums that certain types of fluid helped dampen the sound, and a very small amount of overfill also helped a little. Also, if you shake the shifter while holding the clutch in, to sort of "center" everything up in neutral, does it help at all? I found a little shifter shake would help with trans rattles a bit, in both the new Cruze I was leasing, and the 99 S-10 I used to have, which itself had a rather annoying problem with trans rattle.
I think the problem is related to the detent on the shift assembly in the trans. It's also one of the things that was changed in the MU9. If the new detents on the shift sleeve and rail could be retrofitted to the MT2, it might be helpful in dampening the vibration; although probably won't totally eliminate it.
Originally posted by dobey: Which fluid are you running in your trans? I've seen reports on some forums that certain types of fluid helped dampen the sound, and a very small amount of overfill also helped a little. Also, if you shake the shifter while holding the clutch in, to sort of "center" everything up in neutral, does it help at all? I found a little shifter shake would help with trans rattles a bit, in both the new Cruze I was leasing, and the 99 S-10 I used to have, which itself had a rather annoying problem with trans rattle.
I think the problem is related to the detent on the shift assembly in the trans. It's also one of the things that was changed in the MU9. If the new detents on the shift sleeve and rail could be retrofitted to the MT2, it might be helpful in dampening the vibration; although probably won't totally eliminate it.
I believe the detent, and synchros were upgraded because of all the shifting complaints associated with the 06 version. One of the changes found to offer shift improvement was actually under filling the transmission which I was informed of by a tech that rebuilds Saab transmissions and later I believe that was actually mandated. The colder the weather, the more difficult it is to shift into 1st gear until it warms up.
The idle rattle is a pretty well know "issue" with the 2006 F40 and likely one of the reasons you can buy a "zero mile" 2006 unit for $550 shipped to your door. Mine was a zero mile unit and the rattle has been present since startup about 3K miles ago. If it was the flywheel being loose, it would also rock as you blip/release the throttle or at every downshift/upshft and that doesn't happen. I also think the frequency of the rattle is too quick for a 28lb flywheel/clutch/pressure plate combo to do w/o a lot more force or vibration.
Here is the video.
Sounds just like my 282 with the aluminum flywheel.
Originally posted by Joseph Upson: I believe the detent, and synchros were upgraded because of all the shifting complaints associated with the 06 version. One of the changes found to offer shift improvement was actually under filling the transmission which I was informed of by a tech that rebuilds Saab transmissions and later I believe that was actually mandated. The colder the weather, the more difficult it is to shift into 1st gear until it warms up.
That's possible. I do know that in all the GM vehicles I've driven, the neutral rattle travelled through the shift assembly and into the shifter, and giving it a little shake in neutral did help it out. Since the newer detents increase the amount of tension in the shift assembly, it also seems logical that it might reduce the vibration by helping to hold things in place a bit better. Just speculating that it might help, given that information. Unfortunately, I don't have an 06 and 07 G6 sitting next to each other to compare them.
Thanks for posting that video - gives us all some idea of what to expect. I think I'm going to see if I can find a used car lot with a G6 to drive, just for fun and comparison.
Originally posted by dobey: Unfortunately, I don't have an 06 and 07 G6 sitting next to each other to compare them.
I read up on several complaints on the G6 forum some years back and my first install of the F40 was with the dualmass flywheel. GM made changes for the second year boxes so the shifting problem must have been pretty bad as was often commented on by review articles and mentioned by owners. I don't recall any complaints about noise with the OE flywheel in place and didn't experience any when I used it so except for difficult shifting in cold weather you're not likely to notice any major difference aside from a more positive feel of being in gear between the two models. Raise the idle rpm up around 1100 and it will quiet down.
Which fluid are you running in your trans? I've seen reports on some forums that certain types of fluid helped dampen the sound, and a very small amount of overfill also helped a little. Also, if you shake the shifter while holding the clutch in, to sort of "center" everything up in neutral, does it help at all? I found a little shifter shake would help with trans rattles a bit, in both the new Cruze I was leasing, and the 99 S-10 I used to have, which itself had a rather annoying problem with trans rattle.
I am running the factory specified/brand of transmission fluid at the revised level of 2.2-2.3 liters. I will have to try the shifter shake to see if it does anything, but the shifter is pretty good at self centering in the 3/4 shift position.
quote
Originally posted by fieroguru:
In another thread someone was saying that the special transmission fluid/gear oil for the F40 was hard to get. The GM part # is 88862472 and I purchased 3 quarts from www.CrateEngineDepot.com for $72.70 shipped. Definitely not the cheapest transmission fluid, but I figured I would start with the GM fluid first.
It shipped the same day and arrived today (from IL). The capacity was revised from 3 liters to 2.2 - 2.3 liters.
[This message has been edited by fieroguru (edited 07-13-2013).]
Originally posted by fieroguru: I am running the factory specified/brand of transmission fluid at the revised level of 2.2-2.3 liters. I will have to try the shifter shake to see if it does anything, but the shifter is pretty good at self centering in the 3/4 shift position.
The shifter problem might be a bit more pronounced in the newer design shifters, than it would be in the Fiero shifter. Even if it doesn't help, Some slight horizontal pressure (to move the select side ever so slightly, but not engage anything), might help as well. I'd like to know if you're getting any vibration in the shifter when the noise is occurring.
Originally posted by Joseph Upson: I read up on several complaints on the G6 forum some years back and my first install of the F40 was with the dualmass flywheel. GM made changes for the second year boxes so the shifting problem must have been pretty bad as was often commented on by review articles and mentioned by owners. I don't recall any complaints about noise with the OE flywheel in place and didn't experience any when I used it so except for difficult shifting in cold weather you're not likely to notice any major difference aside from a more positive feel of being in gear between the two models. Raise the idle rpm up around 1100 and it will quiet down.
I've seen complaints of noise in totally stock vehicles. And I've certainly experienced similar issues in GM vehicles, with or without a dual mass flywheel. The dual mass flywheel certainly helps, but it doesn't totally eliminate the noise. I even experienced it in the 2011 Cruze Eco I had for a while, which has the M32 transmission, and a tiny Ecotec. And I don't disagree that some of those changes are certainly related to complaints about shifting. I'm not at all trying to dispute that. However, depending on what is vibrating exactly, they may also help with the noise issue.
I'm just trying to collect some info, to help affirm or dispute my suspicions about where the noise is originating, based on what I've read about it, and what I've experienced with various GM transmissions personally. I think it's worth the little bit of study, even if it turns out to be purely academic.
Originally posted by dobey: I've seen complaints of noise in totally stock vehicles. And I've certainly experienced similar issues in GM vehicles, with or without a dual mass flywheel. The dual mass flywheel certainly helps, but it doesn't totally eliminate the noise. I even experienced it in the 2011 Cruze Eco I had for a while, which has the M32 transmission, and a tiny Ecotec. And I don't disagree that some of those changes are certainly related to complaints about shifting. I'm not at all trying to dispute that. However, depending on what is vibrating exactly, they may also help with the noise issue.
I'm just trying to collect some info, to help affirm or dispute my suspicions about where the noise is originating, based on what I've read about it, and what I've experienced with various GM transmissions personally. I think it's worth the little bit of study, even if it turns out to be purely academic.
Understood, but they (GM) know what the cause of the noise is, it's a characteristic of the design. Do a little more research on the gear arrangement and that should help you pinpoint more specifics.
I pioneered the installation of the 6 speed into the Fiero & we've installed 45 or more of them over the years. Every one of them has had a 1 pc. F/Wheel. I had a customer who was part of the development of this transmissions' use in the U.S. by GM. He was a great help & also helped me gather some facts on these transmissions. (more on that later)
Out of those 45, only 4 or 5 had the rattle. All of the others had no rattle. That's only 10%.
I documented this several years ago on this forum with pictures & the like. I even had a cut-away 6 speed transmission & showed a picture of where the rattle was coming from.
The 1st time I heard the rattle, I was quite upset. We removed that transmission & installed another one from the same group of 15 of the EBay transmissions that I had bought.
Two days later, when we got it back together, it had no rattle at all.
Yes, when the clutch is released quicker the noise seems louder than when released slowly. But I don't see how that can be related to several of the theories I've seen here.
When I documented it before on PFF, I put the blame on the 3rd to 4th shifter ring & fork. With my cutaway transmission in neutral, I can manually move that ring back & forth (without moving the fork) & get a similar noise.
You can try this to see if it helps. On a 6 speed your shifter should be setup so that when the lever is released in neutral the shifter "centers" at the 3rd to 4th gate. With the car running, pedal out in neutral, gently move the lever towards 3rd or 4th gear & the noise should abate.
Other myths debunked?????
A few other facts I learned along the way.
On the G6 6 speed between the 2006 & 2007 model years the 3rd, 4th, 5th & 6th gear ratios changed ever so slightly. That made all of the 6 speeds GM had in the production cycle surplus..... what does GM do with hundreds or thousands of "surplus" parts? They sell them in one lot by the semi truckload to the highest bidder. What does the highest bidder do with them? In the case of the G6 6 speeds, they sell them off on EBay thru several high end junk yards. There's nothing wrong with the transmissions on EBay, they were, at one time, headed for the G6 assembly line before some engineer got the notion to slightly change some gear ratios.
During development of the U.S. version of the 6 speed, GM was testing the 3.9 & 6 speeds in 05 G6 4 door cars. One day a little birdie, called me to tell me that they had totaled one of the test cars by rolling it over on the test track. I was told what junk yard the car was going to & when. I drove up there & bought that driveline & over the next few months I developed the parts to install that 6 speed into my LS1 PFF Finale Roadster. As it turns out I was driving a 6 speed Fiero 3 weeks before the G6 6 speed was on the dealer floor.
BTW, that 6 speed didn't rattle either.
I still have that 1st transmisison that had the rattle in it....... some day, I'm going to cut a small hole in the top of the case & put it in a car to check the rattle. Hopefully it will rattle & I can play with it.
Thanks
Archie
[This message has been edited by Archie (edited 07-13-2013).]
Originally posted by Archie: When I documented it before on PFF, I put the blame on the 3rd to 4th shifter ring & fork. With my cutaway transmission in neutral, I can manually move that ring back & forth (without moving the fork) & get a similar noise.
Thanks Archie for that long post.
This description of the cause of the noise actually fits well with my "theory" if you want to call it that. It also fits with what I experienced in my Chevy Cruze with the M32 6 speed, and the way that playing with the shifter a little in neutral will cause the noise to go away, or quiet down. And more so, it also fits with my suspicion that the detent change on the 07+ F40 which have a bit more tension between the shift sleeve and shift rail, and might thus reduce the amount of play in that ring while in neutral.
I don't currently have the resources to try it, but it would be interesting to take an MT2 that definitely has the noise, and an MU9, and swap in the parts for the new detent system, to see if it does quiet the noise down at all. I don't have a spare of each to split open, or technical diagrams or full parts diagrams of the transmissions, but I think it might help.
Anyway, thanks again for the detailed post. It was helpful.
I went out and did some playing with the shifter while it was idling in neutral:
Wiggling the shifter side to side and even pushing it all the way to the 5/6 and R gates had zero change in the rattle. Pulling the shifter back/forward gently to 3 or 4 (and all other gears for that matter) also had zero change in the rattle.
Not every F40 does it so not every rattle from an F40 equipped car has to be the transmission. It is likely, but getting fixated on a solution to a problem tends to make you ignore other things that may be even worse problems. Larry
Not every F40 does it so not every rattle from an F40 equipped car has to be the transmission. It is likely, but getting fixated on a solution to a problem tends to make you ignore other things that may be even worse problems. Larry
