Cobalt Transmissions

BAR-AIR

Well-Known Member
Good Evening,

The three basic transmissions that where available for the Chevy Cobalt, HHR and Saturn IONs.

- 5 speed F35 (MU3) manual
- 5 speed F23 Getrag manual
- 4 speed 4T45E automatic

Granted there is the F40 and a couple of other ones that will also bolt up to the Ecotec...

Have a question with regards to the F35 (MU3) with the G85 LSD option. I understand it has LSD which is Limited slip differential but what does it actually do to enhance performance. (Both wheels in a stock F35 are drive wheels correct?). Not just going to give a one wheel peel with the transmissions without LSD.

THX,
Bruce
 

Desert Sasqwatch

Goblin Guru
Bruce, found this short but good explanation of a 'standard' open differential versus a limited slip differential. There are other more in-depth and technical explanations on the web if you are interested.
 

BAR-AIR

Well-Known Member
Good Morning,
That is the best explanation that I have seen. The next question is can a stock F35 transmission case be modified into a LSD model. (Cost prohibitive???) Similiar to changing a final drive on the 4T45E transmission in “BLUE” from a Cobalt to an HHR final drive.
THX,
Bruce
 

Desert Sasqwatch

Goblin Guru
Bruce, the F35 manual trans did come from the factory with a LSD, it is the 'G85' code that is referred to so many times here in the forum. If you have a 'standard' F35 (non-G85) it can have a LSD installed, but that can get expensive. This is due the need for specialty tools to disassemble, install and reassemble the transmission. If you Google the F35 rebuild, you will see what I am talking about. Another option is to purchase a rebuild F35, but these are not cheap either, running $2800 plus on many sites on the web. The third alternative is to get a low mile (if it can be found) F35 from a boneyard or from someone selling one outright. I researched this in-depth before I purchased my donor and my kit, knowing I would be building a manual car, and went with the F40 for many reasons - all of which are found in my Build thread.
 

Desert Sasqwatch

Goblin Guru
The Quaife is a Torsen design with ring and multiple planetary gears (6 of the them in my F40 Quaife) that mechanically directs torque to the wheel that is losing traction. It cannot do 100% torque transfer, but will divide torque based on the design - my Quaife can split torque up to 75/25%, it is a more aggressive 'track' version. And I don't need any special tools to disassemble, install and reassemble the LSD into my F40. I will be posting pics at some point in the future when I get this completed.
 
Not to make this a classifieds post... but I have an F35 I'm not using (F40 guy here). My donor shipped with the magical G85 code according to vin decoder. It was a totaled car (rear-ended), but it still drove fine. I put about 75 miles on it, and it seemed to shift great. The donor had 101k miles though, so no telling if it ever had a clutch. Haven't taken it off the engine yet. If you're near OK, hit me up in a private message if interested. I'm about to start going Facebook Marketplace crazy posting Cobalt crap.
 

BAR-AIR

Well-Known Member
Good Morning,
Transmission questions....
Will the F35 bolt up to a 2.4L Ecotec? I was told last night that it might not... seeing that the two were never used together... So I guess the question is has anyone used the two together and what additional (possibly a 2.0L clutch ass’y???) parts will I need.
THX,
Bruce
 

ccannx

Goblin Guru
Not to make this a classifieds post... but I have an F35 I'm not using (F40 guy here). My donor shipped with the magical G85 code according to vin decoder. It was a totaled car (rear-ended), but it still drove fine. I put about 75 miles on it, and it seemed to shift great. The donor had 101k miles though, so no telling if it ever had a clutch. Haven't taken it off the engine yet. If you're near OK, hit me up in a private message if interested. I'm about to start going Facebook Marketplace crazy posting Cobalt crap.
Where are you located ? I have a 200k donor and am looking for a spare trans in Richmond, Va
 

ccannx

Goblin Guru
Yes, you are correct, the wheel with traction gets the torque. Should have said directs the torque away from the wheel losing traction. Thanks. :)
Biggest problem with an open diff that I have noticed is that in tight corners and long sweepers weight transfer to the outside drive wheel and off of the inside drive wheel will cause power to go to the wheel that is unloaded. The loss of power to the ground feels almost like fuel starvation. I noticed it at New Hampshire in corner 3 driving the Poorsat which is mid engine RWD and also autocrossing my MR2 . Autocrossers usually fix this with a huge front swaybar to keep the rear inside planted better but that could lead to a nasty push in a mid engine car.
 
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Desert Sasqwatch

Goblin Guru
Good Morning,
Transmission questions....
Will the F35 bolt up to a 2.4L Ecotec? I was told last night that it might not... seeing that the two were never used together... So I guess the question is has anyone used the two together and what additional (possibly a 2.0L clutch ass’y???) parts will I need.
THX,
Bruce
All Ecotec engines - 2.0, 2.2, 2.4 - have the same transmission bolt pattern.
 

BAR-AIR

Well-Known Member
Good Afternoon,
Has anyone looked at possibly using the stock Fiero Getrag shifter on the F23, F35 or F40 transmissions? FieroGuru has a kit that uses the stock 5 speed shifter as either a 5 or 6 speed with a reverse lock out. The nice part if it works, you would run the cables directly forward and into the back of the shifter. That would eliminate looping the cables around the back of the transmission to the DF supplied bell cranks in front of the stock Cobalt shifter. Seems like a really nice setup... (seeing that the Fiero’s shifter is setup for rear cables and connecting to a front wheel drive transmission mounted to the rear of the car).
9B33C7EF-F736-4C77-9794-1D8F01DF0DBE.jpeg

I picked this one up just to play with....
THX,
Bruce
 

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