F40 6 speed with high torque engines

[goober07]

Hello, I'm new here to this forum. I have a few questions about the F40 6 speed transmission from a 2006 G6 and thought this was the most logical place to ask.

I'm going over the idea of swapping one of these transmissions into an 1985 Fiero GT next year. I've already got a 3800SC installed (l32 set up with l67 throttle, fuel rails and wiring). My main goal is simply to have a manual transmission that is a good deal stronger than what the Fiero came with.

I know the F40 is listed as 295Ft lbs of torque. That's fine for my mildly modded 3800, but I'm curious how much this transmission can really take. 295 wont be hard to pass if I do heads/cam... I'm not insanely abusive, I dont drop the clutch, but I want to be able to run a good 1/4 mile without fear of my transmission simply blowing apart.

What kind of power do you guys normally throw at it? what failures have there been? Most threads I read are over a year old, and I'm trying to get some more up-to-date info. Those threads often state 295 ft lbs and leave it at that, with no actual user experience.

[ragingfish]

Re: F40 6 speed with high torque engines

With all the issues people seem to be having with the F40, I wouldn't waste your time swapping it in. Sounds like when it is operated even well under it's maximum rated torque spec it is causing a lot of headaches or failing outright.

[Blackrider]

Re: F40 6 speed with high torque engines

No one has pushed it to the breaking point.

[TLS2000]

Re: F40 6 speed with high torque engines

Nope, we break the axles free before we break the tranny.

[goober07]

Re: F40 6 speed with high torque engines

Thanks for the quick replies
but there seems to be one conflict... two statements that the trans has held up fine to the point where axles are the weakest link vs:

With all the issues people seem to be having with the F40, I wouldn't waste your time swapping it in. Sounds like when it is operated even well under it's maximum rated torque spec it is causing a lot of headaches or failing outright.

What issues? What people? What circumstances? I'd like as many examples of how well they do or don't hold up before I invest the time and money into swapping one for my old 4 speed muncie...

Obviously I don't own a G6 haha and this is the first I've been to a G6 forum... if this has been covered in another thread just post a link and I'll about it

[TLS2000]

Re: F40 6 speed with high torque engines

Basically:

The transmission is sometimes hard to get into certain gears. If you skip shift, sometimes it will grind. A lot of the complaints have had to do with poor quality on the clutch. I think another complaint is that the cables sometimes get tangled or screwed up.

Blackrider and Kman have had the most problems I think.

[goober07]

Re: F40 6 speed with high torque engines

In my setup, it'll be a custom flywheel and clutch from V8archie, so defects in a stock clutch wouldn't affect me really. Also the cables and shifter would be totally different in my application.

Thanks for the info. Sounds like the transmission hasnt really failed from too much torque, just difficult to shift sometimes. My muncie is a freakin pain so I don't think that's really going to bother me much.

[dre256]

Re: F40 6 speed with high torque engines

Unfortianlly, the two people that did have the most problems with there 6spd F40s dont own them anymore. I think thats about the first thing both of them where happy about, no more F40.

Problem also with the F40 besides hard to get into gear and grinding is the clutch like mentioned above, there is no aftermarket clutch for it. Your stuck with the expensive stock clutch.

Off top of my head, the F40 is rated at 295lbs of torque but only 245 HP.

[goober07]

Re: F40 6 speed with high torque engines

I don't have a lot of details on the conversion kit I would be using, but it is not a stock clutch. It's going to be used with something similar to the spec stage 3 clutch. It won't be the dual mass flywheel from the G6 either, to my understanding.

[08blackgt]

Re: F40 6 speed with high torque engines

i say stick wit the muncie. havin a muscle car background myself that is one of your better options imo. im kinda glad i wasnt able to get the f40 after readin bout the headaches some of these guys have had. what do you plan to put this in btw?

[globalepsilon]

Re: F40 6 speed with high torque engines

What issues? What people? What circumstances? I'd like as many examples of how well they do or don't hold up before I invest the time and money into swapping one for my old 4 speed muncie...

My experience with the F40 has been very good (stock engine output). My first F40 went 40,000 miles with zero problems. The second car is also good so far. Here are specifications from GM if you haven't already seen them. Note that the ratios changed between 2006 and 2007. The shift sleeve and rail were also improved for 2007.

2007 GME Germany F40 ( MU9 )
Type: transverse front wheel drive, six-speed manual transaxle
Engine range: GM 3.9L V6 ( LZ9 )
Maximum engine torque: 245 lb-ft ( 333 Nm)
Maximum gearbox torque: 295 lb-ft ( 400 Nm )
Gear ratios: MU9
First: 3.769
Second: 2.040
Third: 1.365
Fourth: 1.048
Fifth: 0.846
Sixth: 0.707
Reverse: 3.538
Final Drive Ratio: 3.55
Maximum validated gross vehicle weight: 3527 lb ( 1600 kg )
Case material: aluminum
Center distance: 197 mm
Fluid type: Castrol BOT 0063
Transmission weight: wet: 56 kg ( 123.5 lb )
Fluid capacity (approximate): 3.1L / 3.27 qt. ( dry )
Power take off: no
Applications: Pontiac G6

[G6Maniac]

Re: F40 6 speed with high torque engines

I have the 06 6speed manual version as well. I'm assuming its the F40, and I have yet to have problems with it.

[goober07]

Re: F40 6 speed with high torque engines

i say stick wit the muncie. havin a muscle car background myself that is one of your better options imo. im kinda glad i wasnt able to get the f40 after readin bout the headaches some of these guys have had. what do you plan to put this in btw?

I plan to bolt it to a 3800 supercharged v6 from a 2005 grand prix, which is currently installed in a 1985 Pontiac Fiero. Fun as hell to drive with the muncie 4 speed, but I would like the 6 better. More torque capacity is really what I'm after though

[Blackrider]

Re: F40 6 speed with high torque engines

I honestly don't think you'll have an issue with it, I doubt its a very weak tranny just fininky. The rating of GM means nothing.

I would say go for it!

[CjLink]

Re: F40 6 speed with high torque engines

i had my clutch blow out really easily, but with heavy launching at the strip

i think with a well made clutch/flywheel you'll be fine, i believe that's the weakest link to the f40