3.9 bell housings

[NateD4]

Does anyone know when the 3.9L vvt engine switched to the new bolt pattern? Which cars and years were which bolt patterns used in?

[robertisaar]

there's more than one bellhousing pattern for the 3.9?

just find one that's attached to either a F40 or a 4T65, those use the classic "gm small metric" stuff.

[NateD4]

I'm looking at using a 2007 6 speed manual, however I have heard they switched to the new Ecotec bell housing sometime between 2006 and 2007. I was hoping to find out for sure so I could get the right engine/trans combo.

[Joseph Upson]

There's one bellhousing, the original. If you're looking at a 2007 you're seeing the 3.6 to 6spd automatic combo under the GTP option, the 3900 for that year would have been a GT model Pontiac G6 the only model to get the F40.

[NateD4]

I thought I had read that the 2007 MU9 F40 transmission shared bell housings with the ecotec.

Also I noticed they still make 3.9s in the impala (2010 model year). Do these use the old or new pattern?

Thanks

[robertisaar]

the F40 has multiple patterns(depending on the engine it is hooked up to), the 3.9 does not.

[NateD4]

What would be on a 2007 G6 MU9?

I am looking at hooking it to a 2010 3.9 from an impala (LZG engine).

Thanks

Nate

[pocket-rocket]

What would be on a 2007 G6 MU9?

I am looking at hooking it to a 2010 3.9 from an impala (LZG engine).

Thanks

Nate

the F40 has multiple patterns(depending on the engine it is hooked up to), the 3.9 does not.

In other words, get an F40 from a 3.9 car and it WILL have the correct pattern for your 3.9.

[NateD4]

Not quite that easy. The trans I'm looking at is already out of the car.

I also want to use a 3.9 with active fuel management.

The only car that has it is the impala and I'm not sure what bell housing it has since it hooked to an auto.

[robertisaar]

i've never seen a FWD impala that didn't use a 4T65. all of those use the same "gm small metric" pattern that go all the way back to the earliest 2.8s at least.

[Joseph Upson]

Not quite that easy. The trans I'm looking at is already out of the car.

I also want to use a 3.9 with active fuel management.

The only car that has it is the impala and I'm not sure what bell housing it has since it hooked to an auto.

It is that easy, you're making it hard. There is one bolt pattern for the GM 3900 V6 no matter what GM car it is from. The only Domestic U.S. GM car that came with an F40 is the 2006-2007 Pontiac G6, no exception. No matter what car the 3900 is from that transmission will bolt to it.

Now what you're going to do about a DOD (AFM) engine bolted to an F40 I don't know, as DOD was not used with the F40 and unless provisions have been found to tune out the BCM/TCM input the PCM will be looking for from the auto trans the PCM will set codes that will affect driveability.

[robertisaar]

http://en.wikipedia.org/wiki/GM_F40

a couple of Saabs used it as well, but they ran Ecotecs which DO have a different bellhousing pattern. so, if it came from an Ecotec car, don't bother with it. if it came from a 3.9 car, you can use it.