V1 Auto to Manual Conversion

[Anks329]

Hi All!

As I wait for my kit, I've been thinking about the next stage of my build and I want to convert my automatic to a manual transmission. Has anyone done this before, any pointers? I was thinking of using the ZZP F35 transmission and adding in a shifter. I know that I would have to get the PCM flashed, what else would I need to do?

Thanks!

 

[Ross]

What engine do you have? I know the standard transmission in a 2006 SS has a P12 PCM, and the automatics have a ECM and TCM. Not sure if the ECM can be used as a PCM.

 

[Anks329]

I've got a 2007 LS base with an automatic transmission, it is a 2.2L engine with an ECM and TCM. Would I need a new wiring harness to go with it?

 

[Adam]

I'm not sure about the wiring and computer compatibility but there are a few physical items that you should consider:

Unless you are doing a custom shifter setup, you will need a different tunnel cap from us to run the manual shifter and hardware that we use. We weld two pieces in front of the shifter for the bellcranks and a piece under the shifter for the cables. You might also want the hard clutch line from us. Both the tunnel cap and clutch line are awkward to ship later so let me know if you want those with your kit so that your swap is easier to do when the time comes.

The shifter cables aren't too bad to ship but they could also ship with the kit to save a little money in the long run.

Also, our F35 transmissions are $650 and I can pack it with your kit if you don't want to pay separate shipping. I don't have a full store up and running yet but I do have a page for the F35: https://store.dfkitcar.com/products/zero-mile-f35-transmission?variant=31345564975174

There is also the F23: https://store.dfkitcar.com/products/zero-mile-f23-transmission?variant=31353293439046

 

[BAR-AIR]

Good Morning,
I know the three automatic transmission Cobalts I have pulled the harnesses out of had the plugs for clutch pedals still in the harness. (Just open plugs - definitely had some confusion trying to identify those plugs later.)
THX,
Bruce

 

[Karter2026]

Good Morning,
I know the three automatic transmission Cobalts I have pulled the harnesses out of had the plugs for clutch pedals still in the harness. (Just open plugs - definitely had some confusion trying to identify those plugs later.)
THX,
Bruce

On the other side of that my 5 speed car had the automatic shifter plugs. Nothing for the TCM though.

 

[DCMoney]

Wouldn't the 2.2l engine need the F23 transmission? Thought the 2.2 and 2.4 has a 6 bolt crank for the flywheel where the 2.0 has an 8 bolt, and from all my research the two are transmissions are not interchangeable without a few custom parts.

 

[Anks329]

Oh man, Adam... you're enticing me to buy the transmission and other hardware and have everything shipped together. Since we've got some time on shipping now, let me think some more and will let you know.

Bar-Air and Karter2026 - good to know about the plugs in the harness. I will keep an eye out for those as I start the wiring harness work this weekend.

DCMoney - No clue, honestly this is the kind of information I was looking for! I'll do a little research into this and post back my results.

 

[Karter2026]

So you may want to read up on this

F35 vs. F23

and also this

F23

 

[Anks329]

Ok, couple of bits of information in case anyone else wants to do this also. Here are the things you will need from DF:

• F23 manual transmission
• manual tunnel cap
• pushrods, bell cranks and hardware for the shifter linkage
• Goblin shifter cable
• clutch line
• clutch pedal mounting hardware

You will also need to re-flash your ECM to handle the manual transmission versus the existing automatic. Thanks to @BAR-AIR I reached out to RDM Ecotecs. They will be able to flash the ECM, and there is no additional wiring work that needs to be done, the existing TCM can stay in place.

 

[Iwanttogofast]

I will be placing my order (hopefully soon) for my Goblin AFTER acquiring my donor car. I have seen quite a few clean, low-mile cars that I was very interested in – until I saw that they are automatics. I was wondering about an auto-to-manual conversion myself, and found this thread.

Anks329 – Did you have any issues? About how much should I expect to spend if I do go this route?

Has anyone else done a conversion?

Thanks in advance…

 

[Rttoys]

I would suggest buying the doner that will have everything you want. It will make life a whole lot easier and far more cost effective. Once you get to building and start making progress, the last thing you’ll want to do is have to modify everything and run into problems that maybe only 1 or 2 people can answer.

Not that you can’t do it, but how much more difficult do you want to make it?

 

[jennam]

@Iwanttogofast I'm swapping my running gear and wiring out in my goblin this fall if you are looking for a running set.

 

[Anks329]

I will be placing my order (hopefully soon) for my Goblin AFTER acquiring my donor car. I have seen quite a few clean, low-mile cars that I was very interested in – until I saw that they are automatics. I was wondering about an auto-to-manual conversion myself, and found this thread.

Anks329 – Did you have any issues? About how much should I expect to spend if I do go this route?

Has anyone else done a conversion?

Thanks in advance…

I haven’t done the conversion yet. I’m building the automatic at the moment and aim to convert it this winter or next winter. I ended up getting the transmission and other parts from DF at the same time as the rest of my kit to save on shipping. It was a total of $750 (less some discount from the powder coating issues). Beyond this, I know I will need to get at least a clutch and reprogram the car.

So, I’m budgeting at least 1k for the conversion.

I don’t think anyone else on the forum has attempted this conversion yet. So, not a lot of knowledge to fall back on when something doesn’t work right.

 

[Tinkles]

Wouldn't the 2.2l engine need the F23 transmission? Thought the 2.2 and 2.4 has a 6 bolt crank for the flywheel where the 2.0 has an 8 bolt, and from all my research the two are transmissions are not interchangeable without a few custom parts.

On this topic. 2.0L LSJs and LK9s have been swapped into Cavaliers/Sunfires with the F23 trans and I am pretty sure the builders didn't have to do anything special with the transmission/clutch. They just used the clutch for the F23.

I think the custom parts come into play when swapping a F35 out for a F23 and physically mounting it to the car. My main experience is with Cavaliers, not Cobalts, so all of the cars came stock with the stronger F23 trans.

 

[DCMoney]

On this topic. 2.0L LSJs and LK9s have been swapped into Cavaliers/Sunfires with the F23 trans and I am pretty sure the builders didn't have to do anything special with the transmission/clutch. They just used the clutch for the F23.

I think the custom parts come into play when swapping a F35 out for a F23 and physically mounting it to the car. My main experience is with Cavaliers, not Cobalts, so all of the cars came stock with the stronger F23 trans.

Thanks for the info, I almost bought an F23 to see what all was needed.

 

[Mirage775]

I understand this is a super old thread, but if I wanted to do this to mine, would I be able to move the engine back .75"-1", in the Goblins' frame, like the other manual cars can? That's one of the reasons I didn't install the supercharger, as Adam said the automatics sit closer to the fuel tank than the manuals do? I would be very interested in swapping to a manual, especially since I can fit in the standard frame fine now

 

[ah.b.normal]

First of all I have never actually swapped any cobalt from auto to manual. I have dug deep into the wiring harnesses though. I will tell you that most difference I have found is in the engine harness. Though the engine and trans harnesses are built together I have found the two are not electrically intertwined. The Speedo sensor is much shorter on the manual and uses a different plug end but that can be found. In the cobalt design the Trans control computer is always separate from the engine computer. So I believe in function the trans harness could have been seperate but was built into the engine harness to ease manufacture.
Off the top of my head a couple of wires from the big black connector, I know one is re-routed to the ECM and another to the 14 pin connector. I would suggest finding a harness from a manual car of the same year and get busy comparing differences. I have torn apart several auto Engine harnesses and weeded out the automatic wiring and found just a few things to change to make a manual harness. It appeared, as I mentioned, the trans harness is integrated into the engine harness for construction convenience.
I have not worked on the possible difference on Body Control Modules between the two types. Please IM me if you desire to dig more deeply into this subject as I have several years of parts to experiment with and I desire more information/ clairaty on this subject.

 

[Mirage775]

First of all I have never actually swapped any cobalt from auto to manual. I have dug deep into the wiring harnesses though. If you want to experiment I will tell you that most difference I have found is in the engine harness. Though they are built together I have found very little difference between the harnesses! The Speedo sensor is much shorter on the manual and uses a different plug end but that can be found. Overall it seems that the transmission harness and Trans control computer is always seperate from the engine computer. So I believe in function the trans harness could have been seperate but was built into the engine harness to ease manufacture. Off the top of my head a couple of wires from the big black connector I know one is re-routed to the ECM and Another to the 14 pin connector. I would suggest finding a harness from a manual car of the same year and get busy comparing differences. I have torn apart several auto Engine harness and

No, it's not that hard, did you read the previous posts?

"Anks329
Ok, couple of bits of information in case anyone else wants to do this also. Here are the things you will need from DF:

• F23 manual transmission
• manual tunnel cap
• pushrods, bell cranks and hardware for the shifter linkage
• Goblin shifter cable
• clutch line
• clutch pedal mounting hardware

You will also need to re-flash your ECM to handle the manual transmission versus the existing automatic. Thanks to @BAR-AIR I reached out to RDM Ecotecs. They will be able to flash the ECM, and there is no additional wiring work that needs to be done, the existing TCM can stay in place."

 

[ah.b.normal]

Wiring differences are few in the engine harness. The hard part for some folks is stripping the speedo wires out of the engine trunk wires. It looks scary but is straight forward. Then finding the correct speed sensor end, f23 and f35 and auto each use a different connector. On the auto VSS is near the right half shaft and on manuals it is near the diff on the left side. Virtually all of the automatic feeds can be cut away and discarded, reducing the size of the engine harness by about a third. And leaving the TCC off as well cleans things up too.

Also you will need to find a clutch pedal that matches your vehicle year. Not sure when they changed but 05-6 used two but 09-10 used a single switch. 07-8 ??? (I need to see on my 07, I have several research victims at my disposal.)
I know I have a 05-6 pedal available. New master cylinder is always recommended by this hack mechanic, me.
On a seperate note does your frame have the clutch master cylinder bracket from the DFFactory? I’ve not seen any automatic Goblins.