The transmission cooling lines were leaking on my 2014 Impala 2LTZ (purchassed new) and were replaced under my GM service plan last year.

The Chevrolet dealer labor charge was about 2 1/2 - 3 hours as numerous things had to be disconnected to replace the lines (sold as an assembly with both lines). If I recall correctly, the dealership had to drain about 5 quarts of transmission fluid to do the change (and replaced the fluid).

I don’t have instructions for you but it was an involved repair.

 

The amount of labor involved, as well as the fluid that needs replacing and the price of parts will likely put you in that $500 range. It's a bear, and the price of parts is never an indication of the amount of work that is actually involved.

 

Which I fully understand that parts price is not equal to work involved. I did inquire how much labor they were charging for and was told 1.3 hours. Even with fluid replacement and a significant up charge in parts price, still doesn't equal the price I was quoted.

I was able to look a little bit closer at the lines on my lunch break today and I believe I found the 2nd line enters the transmission. It seems to be basically under the coolant overflow tank near the firewall. It's gunna suck getting to that one but maybe won't be terrible after removing some items in the way.

 

Well I have it done minus the line going to the lower radiator/cooler. I cannot get it to snap into the fitting. It wasn't a terrible job, just tedious. Here's a walk through if anyone else wants to attempt this.

I removed the engine and radiator cover. I also uncapped the computer next to the battery and laid it off to the side for access.

I disconnected this wire to gain better access to the upper line where the upper line connects to the radiator.

The line goes under this gear select bracket. It is held on with 2 13mm bolts. Remove the bracket.

Squeeze the gear select cable here to remove from the bracket. BE VERY CAREFUL NOT TO PULL THIS CABLE TOWARDS THE FIREWALL, YOU WILL DISENGAGE PARK.

AGAIN, DO NOT ACUATE THIS LEVER. Please put chalks or something behind your wheels.

At this point I was able to remove the lines from the transmission. They are held in with 13mm nuts. The rear one I was able to stack some extensions to get it on the nut before attaching the ratchet.

To remove the lines from the radiator/cooler I used a 3/4 inch crows feet to spin the fitting the line goes into off.

I removed the fittings because I was replacing them. A while you're in there repair. Here is the part number.

I replaced the fittings with a 3/4 inch ratchet and got them snug. No need to go crazy considering it's going into a plastic end tank.

Now replacing the lines is a bit of a pain but it's just trial and error for the best way to do this. The rear line I got was not exactly the same as the one removed. It still fit but added to the problem solving. I did have to remove the battery and battery box to get this line back in. The new line does not go under the gear select bracket. The battery box is held in with 3 13mm bolts. The 3rd bolt is behind the battery box and you just have to loosen in, not take it all the way out.

I waited until I had the lines laid out before tightening them down. The lines going into the transmission do not need to be super tight, just snugging them down is fine.

I hope this helps other that come across this problem. Take your time and you can get it done.

 

Well I have it done minus the line going to the lower radiator/cooler. I cannot get it to snap into the fitting. It wasn't a terrible job, just tedious. Here's a walk through if anyone else wants to attempt this.

I removed the engine and radiator cover. I also uncapped the computer next to the battery and laid it off to the side for access.
View attachment 168709

I disconnected this wire to gain better access to the upper line where the upper line connects to the radiator.
View attachment 168710

The line goes under this gear select bracket. It is held on with 2 13mm bolts. Remove the bracket.
View attachment 168711

Squeeze the gear select cable here to remove from the bracket. BE VERY CAREFUL NOT TO PULL THIS CABLE TOWARDS THE FIREWALL, YOU WILL DISENGAGE PARK.
View attachment 168712

AGAIN, DO NOT ACUATE THIS LEVER. Please put chalks or something behind your wheels.
View attachment 168713

At this point I was able to remove the lines from the transmission. They are held in with 13mm nuts. The rear one I was able to stack some extensions to get it on the nut before attaching the ratchet.
View attachment 168714

To remove the lines from the radiator/cooler I used a 3/4 inch crows feet to spin the fitting the line goes into off.
View attachment 168715

I removed the fittings because I was replacing them. A while you're in there repair. Here is the part number.
View attachment 168716

I replaced the fittings with a 3/4 inch ratchet and got them snug. No need to go crazy considering it's going into a plastic end tank.

Now replacing the lines is a bit of a pain but it's just trial and error for the best way to do this. The rear line I got was not exactly the same as the one removed. It still fit but added to the problem solving. I did have to remove the battery and battery box to get this line back in. The new line does not go under the gear select bracket. The battery box is held in with 3 13mm bolts. The 3rd bolt is behind the battery box and you just have to loosen in, not take it all the way out.
View attachment 168717
View attachment 168718

I waited until I had the lines laid out before tightening them down. The lines going into the transmission do not need to be super tight, just snugging them down is fine.

I hope this helps other that come across this problem. Take your time and you can get it done.

Proud of you. Thank you for the detailed write-up.

 

Update on the lower line. As I said above I could not get it to seat. There isn't much of a place to get leverage. I took a photo to make sure there were no obstructions. It was clear. I sprayed some PB Blaster on the line, lined it up the best I could, then used a scrap 2x4 as a hammer. That was enough to send it home. Started the car up and we have 0 leaks. It was a long day but got it done.

Now to just just find my 3/4 crows foot I dropped onto the plastic under tray and disappeared.