Transmission Interchange

[Thewrenchartist]

Hello everyone, hopefully someone will be able to clarify for me. I have a 2012 Sonic 1.8 L Automatic. My transmission blew and I'm trying to replace it. I've found a low mileage from a 2015 Sonic with about 10000 miles on it. I'd like to know the following?

1. Is 2015 trans compatible with my 2012 Sonic?
2. If yes, do I swap my TCM to the 2015 tran?
3. If the 2015 is not compatible with my 2012 engine, can I put in the engine from the 2015 Sonic on my car along with the 2015 transmission?

Thank you so much for your assistance

 

[92dakota]

Quote form Blue Moon Sonic .. on my thread..

As a side note, you don't need a year correct transmission in these cars. I have a 2014 trans in my 2012 with no issues despite the TCM programming and hardware differences between the two. You can even throw the RS auto in there and it'll make the car less lethargic to drive due to the final drive ratio change.

 

[68bugonair]

I would have thought that the shift points would be different, good to know


Sent from my iPhone using Tapatalk

 

[Thewrenchartist]

Hello guys,

There's still something else I'd like to clarify, please. Can I remove the computer (just the computer) from my 2012 TCM and install it on the 2015 TCM so I don't have to program it after installation? Or do I have to install the 2015 transmission with its original TCM?

http://www.csmans.com/control_solen...ontrol_module_assembly_installation-2507.html

 

[Thewrenchartist]

Hello guys,

Just wanted to give you a quick update on the transmission replacement on my Sonic. Over the weekend (After Thanksgiving), I finished putting everything back together.
1. The 2015 Sonic trans bolted perfectly onto my 2012 Sonic engine. The only difference was one bolt on the bottom that was not the same size.
2. I refilled the trans with Amsoil Signature ATF. I added about 7.2 quarts while the engine was running and the trans on Park until the fluid came out of the level hole on the driver side of the transmission.
3. I shifted several times from P to all the other gears and back while the car was parked inside my garage.
4. There are no error codes displayed for the transmission (Fingers crossed).
5. I will be testing the car on the road sometimes this week and will let you know how it drives.
6. The only new issues I have now are: a) Code P0171 System too lean (Bank 1) b) The brake pedal is very hard. I will be working on fixing these soon.

Regarding transmission programming, can anyone confirm whether I need to go to the dealer or not to have the transmission programmed or can I just leave it as it is since there are no transmission codes?

Thanks a lot!

 

[Thewrenchartist]

Update on Trans after install

I tested the car on the road and it shifts smoothly. Apparently, I don't have to re-flash the transmission.

By the way, the code P0171 was due to a tube that was inadvertently disconnected from the brake booster while I was installing the transmission. Everything works fine now.

I want to thank all of you for your assistance.

 

[hawkeye75]

Looking at replacing my 2012 1.8 Chevy Sonic's transmission with a 2014 version, hope all goes well! Relying on the 3 people on this forum that said it would be fine to not make me be out $500

 

[MontyG]

Looking at replacing my 2012 1.8 Chevy Sonic's transmission with a 2014 version, hope all goes well! Relying on the 3 people on this forum that said it would be fine to not make me be out $500

Hawkeye75,
I'm in the same boat. I have a 2012 LT Hatchback and found a 2014 transmission with the same three letter identifier. Did you install the 2014...any issues?

 

[hawkeye75]

Hawkeye75,
I'm in the same boat. I have a 2012 LT Hatchback and found a 2014 transmission with the same three letter identifier. Did you install the 2014...any issues?

No issues! Got mine installed a week ago. Have a 2012 LT Sedan, and got a 2015 transmission installed with no problems. Any 2013-2015 automatic transmission should work, regardless of the 3 letter identifier. I asked the shop to keep the 2012's transmission control unit in cause I saw someone else on a different thread suggest it, but it didn't end up moving. So just swapping the entire transmission should work. The fuel efficiency does seems to be a bit worst, but I will have to drive it a bit more to get a definitive answer. Good luck on the install!

 

[MontyG]

Thanks for the quick response....much appreciated. I feel better now about moving forward with the 2014 transmission. I had one transmission guy tell me it should work because it's the same 6T30 transmission...just may need the TCU reflashed. The others, including Chevy Parts at Dealer, just said it's not recommended and shrugged their shoulders. The 2012 Sonic obviously had transmission issues...seems GM pushed it off on the consumer instead of correcting/backing up their product. I've tried several things...changing the fluid, new TCU and reflashing. Now, the codes are P0700 and P2723....no reverse and basically no forward gears, top speed 8-10 mph. I feel like the only option is another transmission....very frustrating. I'll provide an update after I'm back on the road. Hopefully, the information can help another.

 

[Kplive]

Quote form Blue Moon Sonic .. on my thread..

As a side note, you don't need a year correct transmission in these cars. I have a 2014 trans in my 2012 with no issues despite the TCM programming and hardware differences between the two. You can even throw the RS auto in there and it'll make the car less lethargic to drive due to the final drive ratio change.

Can a 6t50 transmission fit inside a sonic???

 

[MontyG]

UPDATE...This is a follow up on my previous post. I purchased a 2014 Sonic transmission...made sure it was a 6T30 for a 1.8L engine. I did select a transmission with the same three letter identifier(GBS). I had the transmission installed into my 2012 Chevy Sonic LT. The transmission I purchased came with a transmission control module(TCM) attached. The 2012 Sonic is running great with a complete 2014 Sonic transmission. I saved a ton of money. I had two shops quote me $4000+....Crazy! I told them the car wasn't worth that much. I had several tell me I had to match another 2012 Sonic transmission into my car for it to work. Why would I want to put another 2012 transmission into my car when the internet is filled with stories of failed 2012 transmissions?!? The average cost of a 2012 Sonic transmission was going between $700-$1200+....again, Stupid Crazy! I found a 2014 Sonic transmission on Ebay with the TCM and torque converter for $425....delivered! This forum helped me decide to buy a different year transmission....hopefully, it will help others.

Again...Thanks to Hawkeye75 for responding to my question and easing my anxiety.

 

[Mr.Optimistic]

I just replaced my 2012 Sonic 1.8 transmission with a 2014. Just wanted to clear some things out after removing my tranny twice. The verdict is the valve bodies are different. Some of the solenoid pack assemblies have pressure sensors , some don't. The valve bodies are not routed the same way either. The transmission case and internals are the same.So it's safe to buy any transmission and long as you use your old valve body and solenoid tcm pack , otherwise make sure the new one you gets is the same.Since mine weren't it started throwing tcm codes.

 

[StillinFront]

Thanks to this thread I just completed a transmission swap in my 2012 1.8L!!!!
I bought a used 2014 transmission with the same 3 letter identifier. It bolted up with no issues. I left the 2014 trans complete(torque convertor, solenoids, and TCM) and it did not throw any codes and works perfect.

 

[baadharley]

UPDATE...This is a follow up on my previous post. I purchased a 2014 Sonic transmission...made sure it was a 6T30 for a 1.8L engine. I did select a transmission with the same three letter identifier(GBS). I had the transmission installed into my 2012 Chevy Sonic LT. The transmission I purchased came with a transmission control module(TCM) attached. The 2012 Sonic is running great with a complete 2014 Sonic transmission. I saved a ton of money. I had two shops quote me $4000+....Crazy! I told them the car wasn't worth that much. I had several tell me I had to match another 2012 Sonic transmission into my car for it to work. Why would I want to put another 2012 transmission into my car when the internet is filled with stories of failed 2012 transmissions?!? The average cost of a 2012 Sonic transmission was going between $700-$1200+....again, Stupid Crazy! I found a 2014 Sonic transmission on Ebay with the TCM and torque converter for $425....delivered! This forum helped me decide to buy a different year transmission....hopefully, it will help others.

Again...Thanks to Hawkeye75 for responding to my question and easing my anxiety.

Hi there, I went on the advice of this forum and went for the 2014 4GBS trans to replace my 2GBS. I found a really low mileage 33K trans from my local scrapyard. I replaced the original-everything bolted up and re-connected everything as it was. I looked at the TCM connector/plug and appeared same number of pin/connectors. HOWEVER-I get in the car and not only will it NOT start...but I noticed the illuminated gear selector on the dash does nothing...No PRND, etc. I made sure linkage was correct and it is. Disconnected battery for like 15 minutes and still NOTHING. Is it possible I neeed to swap the old TCM?? HELP, Please!!

 

[Mr.Optimistic]

Hi there, I went on the advice of this forum and went for the 2014 4GBS trans to replace my 2GBS. I found a really low mileage 33K trans from my local scrapyard. I replaced the original-everything bolted up and re-connected everything as it was. I looked at the TCM connector/plug and appeared same number of pin/connectors. HOWEVER-I get in the car and not only will it NOT start...but I noticed the illuminated gear selector on the dash does nothing...No PRND, etc. I made sure linkage was correct and it is. Disconnected battery for like 15 minutes and still NOTHING. Is it possible I neeed to swap the old TCM?? HELP, Please!!

Try swapping the valve bodies you can do it while it's in the car it shouldn't take more than an hour or two. Make sure you swap the top of the valve body and the bottom part. The solenoids come out first with the TCM attached and the valve body it's right under that ,change that too.

 

[baadharley]

Try swapping the valve bodies you can do it while it's in the car it shouldn't take more than an hour or two. Make sure you swap the top of the valve body and the bottom part. The solenoids come out first with the TCM attached and the valve body it's right under that ,change that too.

Hi there, thanks for the quick reply. Yes, I plan on getting back the old trans and swap out the TCM and valve body...just seemed weird car won't even start, Dang computers!! I usually have the worst luck, so should have known it wouldn't just work swapping out the newer trans. I wil update, once I can get the parts. Thanks!

 

[Mr.Optimistic]

Hi there, thanks for the quick reply. Yes, I plan on getting back the old trans and swap out the TCM and valve body...just seemed weird car won't even start, Dang computers!! I usually have the worst luck, so should have known it wouldn't just work swapping out the newer trans. I wil update, once I can get the parts. Thanks!

Wait did you say no park reverse neutral or drive notifications. That's most likely you're a part of neutral safety switch. Make sure it's connected properly. It might be bad on its own. When that does not work the car usually doesn't start. It's right under the Transmission Metal shifter thingy On top of the transmission.

 

[baadharley]

Wait did you say no park reverse neutral or drive notifications. That's most likely you're a part of neutral safety switch. Make sure it's connected properly. It might be bad on its own. When that does not work the car usually doesn't start. It's right under the Transmission Metal shifter thingy On top of the transmission.

That is correct, no shift indicators. I even did the manual override on the shifter to cycle thru the gears, as the shift interlock solenoid does not even click when brake pedal and ignition on all the way. Thanks for the info, but from what I can tell, according to repair manual and exploded view...the neutral safety switch is inside the trans and part of the TCM. I need to drain the fluid and take of pan anyway...sooo. Thx!

 

[StillinFront]

Hi there, I went on the advice of this forum and went for the 2014 4GBS trans to replace my 2GBS. I found a really low mileage 33K trans from my local scrapyard. I replaced the original-everything bolted up and re-connected everything as it was. I looked at the TCM connector/plug and appeared same number of pin/connectors. HOWEVER-I get in the car and not only will it NOT start...but I noticed the illuminated gear selector on the dash does nothing...No PRND, etc. I made sure linkage was correct and it is. Disconnected battery for like 15 minutes and still NOTHING. Is it possible I neeed to swap the old TCM?? HELP, Please!!

I just swapped by bad 2012 2GBS for a 2014 4GBS as well. I left the 2014 stock and had zero issues. Please start by checking the electrical connections. The connector on the ECU is known to easily break when you disconnect it.