blrt

I've had my 4:45 F35 for many years and I am looking to upgrade to a stronger and Hwy friendlier Transmission like the F40.
Ideally I would preferred the F35 6spd Quaife gear set but they are no longer available. B3 upgrade 4:05 would be ok but wouldn't be as strong as the F40.
I am leaning towards OTTP because they offer a complete new F40 with the option LSD installed and a Spec clutch that I can purchase at the same time.
I did a lot of reading on the different issues associated with the F40. Ie. cruise control, clicking axles noise and vibrations? Are these just isolated cases or are they common with all F40 for the Cobalt?
How do you all like the upgrade and how long have you had it?

cw383

iTrader: (6)

I have used the F40 Buick transmission using the OTTP kit. I have encountered no cruise issues or axle clicking, but I am using the drivers side axle from OTTP. Some say factory axles work no issues, I didnt want to gamble and the axle was cheap enough. Now i have used 2 different racing clutches. The one with the Spec aluminum flywheel and also the one which uses the factory dual mass flywheel. The Spec flywheel was very loud, like a rod knock idling with the clutch out. Also seemed to have more vibrations then the dual mass by a good measure. I am now using the one which uses the factory dual mass. Much much quieter. You must use caution here, Spec will try to sell you the wrong part. I use the factory Regal flywheel, the pressure plate would not bolt up to it. They insisted it was the right part, and I even confirmed the number on the flywheel was the right part. I had to return it and order a Saab clutch kit for over $100 more. I warned them if they dont fix it someone else will get screwed too. AA few weeks later one of my buddies with a regal is complaining the clutch kit doesnt fit. Same thing, they didnt listen. No one ever offered anything in the way of a discount or even an explanation. Not happy. If you are using factory dual mass, which I recommend, contact me for the RIGHT part number.

I have had the F40 for about 2 years now, very happy with it. Gearing is pretty similar to 4.45 in gears 1-3 with a longer 4th gear then super steep 5 and 6

USMCFieldMP

iTrader: (1)

I have no experience with the F40 - but I did swap to the F23 a year ago. It's a way cheaper swap, the transmissions are multiple times more plentiful, it can be done with mostly stock/already utilized parts (I'm unsure about LNF axle options; LSJ's can just use base model axles), there are five final drive options, and they're lighter than the F40 - all wins in my book.

I did the entire swap for under $1000 - and the majority of that cost was OTTP's billet mounts and their short throw shifter; all things that I didn't HAVE to use (in fact, if I did it again, I wouldn't get the STS).

blrt

Thanks for the feedback. This is really helpful.
You are right I have had dual mass flywheel and aftermarket ones on a different car. I would stick with stock vs light weight ones.
What is the stock Saab clutch rated for? I need something that will hold 400whp and torque. And this is the reason I was looking at the Spec Stage 3? What are my other options if Spec has fitment issues?

blrt

Thanks for this. That is a lot cheaper for sure. The only concern is where to find a reliable good condition used F23? If I can get a good used or a new one, that would be an option for sure. Which is more robust between the two trany?

USMCFieldMP

iTrader: (1)

There are lots of high horsepower Cavaliers that have been using the F23 for decades. The F23 and F40 are more robust than the F35 because they use a 3-shaft design, versus the 2-shaft design of the F35.

And you can definitely find low mileage, good condition examples. Of course, when they only cost $200... who cares?

I know the DF Goblin company had a bunch of stock of brand new, never installed F23's a while back. No idea if they still have them though.

Mine was a 30 or 40k mile XFE trans. The XFE had comparable 1-4 ratios as the 4.05 F35, but the 5th gear was longer. I did have cruise control problems in 5th gear; no other. So there is something coded into the BCM that gives some cars trouble with longer gear ratio transmissions.

Here's the transmission ratio spreadsheet that I created: https://www.cobaltss.net/forums/tech...dsheet-329296/

Very useful for picking what final drive you want.

AfterShok

Let me know how this goes as I am interested as well over the winter!

blrt

Good Info thanks. I went over to their site/forum for a quick look. It appears they have it listed on their Web Store? This is a Getrag F23 for our Cobalts? The last conversations on their board was in Feb 2022. I have sent them an email about it and LSD installed. I will see what the say about if they can ship to Canada?

​​​​​On their website it had described the F23 was suppose to be on the 2008 Cobalt but never did? What and where do I buy the mounting hardware to make it work on the LNF? What clutch kit do I need for THis to hold my hp range?

blrt

I did a quick search and motorcity transmission over in Flint MI has brand new Regal F40 for 1k usd but they don't ship to us. OTTP has them included in their kit so no need to buy from them.

blrt

https://dfkitcar.com/forum/index.php...ion-swap.2502/

Found this over on the DF Forum. Interesting. The axles on the F23 is smaller then the F35/F40. That might be an issue for anyone that has a high HP LNF?

USMCFieldMP

iTrader: (1)

F23 was mounted to the 2.2L and 2.4L Cobalt/Ion/G5/HHR from 2004 to 2010 (just with a couple different final drive ratios). It mounts to the block exactly the same - you MUST still use the thin metal shim between block and transmission. You can keep whatever clutch system you already have. A lot of people still use the F35 TOB with a "customized" clutch pipe, but I've been using an F23 TOB. You need a front and upper transmission mount for the F23. You need the F23 shifter cables and shifter box (people have modified the F35 shifter box to work, but it is seriously a 10-15 minute swap job... I feel like it would take longer to do the modifications).

Buy the Premium NAPA axles - not that O'Reilly junk that they listed there. I'm moving 450-500hp through my NAPA axles - no issues yet.

cw383

iTrader: (6)

Stock Regal clutch may work on 400 for awhile. I destroyed one in 4 months at 500+ though. But I did do a lot of drags. The Spec one that works with factory dual mass works well, but the clueless people at Spec will send you the wrong one. You have to use the Saab one that costs $100 more. The one they make to fit the 2013 Regal literarily does not fit the 2013 Regal

blrt

dfkit doesn't ship to my area.
Good to know that the F40 Regal can take many 500whp drag passes. A lot more hp then my setup.
It is a lot of $$$ for a transmission use for the street. By the time it gets into my hands plus installation and taxes. Hmm... lol..
With all the bells and whistles (LSD / DSS), it would cause me over $6K. Lol... I have to think this over... It is good to know all the options out there.
A less expensive option may be with E3 Design / Wagon SS 4:05/F35 with the LSD. At lease I can reuse my clutch/axles.
Thank you all for your insites and experiences with the all the different options available to consider.
​​​​​

USMCFieldMP

iTrader: (1)

*whispers* eff twenty three...



One of the highest horsepower Deltas that I know about - user armcclure - runs an F23... and he works at ZZP, so cheap parts are at his disposal.

Ferrai

hi can you give me correct parts number for clutch and flywheel?

blrt

Has any one done the F23 swap for the LNF?