Transmission Cooler Line Popped Out

bowtiegurl · Dec 11, 2024

I replaced the radiator in my 2007 Yukon SLT with a Spectra Premium CU2423.
I drove about a mile and back when I noticed a little smoke from under the hood. Opened the hood to find transmission fluid all over the engine. The top transmission cooler line had popped out. I'm sure I had seated it fully because I heard the click as it seated behind the C clip.I bought a new fitting reseated the line, filled back up with 7-8 qrts of fluid, let it idle watching the cooler line. The line held but when putting into any gear it does not go. Just revs up. All the stories I've read of this happening to other people their transmission's are fine after putting fluid back in. Is there something else I need to do or check? Can't afford to take it to a shop to have it looked at.I let it idle with fluid filled for 25-30 minutes and the transmission got up to 207•. With my old factory radiator it stayed around 178•. Also I squeezed the top radiator hose and I could squeeze all the way to the middle. The hose was warm but not hot. Any ideas?

swathdiver · Dec 11, 2024

With the engine running and your foot on the brake, shift the truck into each gear and leave it there for thirty seconds. So put her into reverse, then neutral, then drive, then low and then go back up the list.

Fluid won't be hot enough yet but check the fluid level on the cold mark. Too much or too little fluid and she won't run right either.

Doubeleive · Dec 11, 2024

bowtiegurl said:
I replaced the radiator in my 2007 Yukon SLT with a Spectra Premium CU2423.
I drove about a mile and back when I noticed a little smoke from under the hood. Opened the hood to find transmission fluid all over the engine. The top transmission cooler line had popped out. I'm sure I had seated it fully because I heard the click as it seated behind the C clip.I bought a new fitting reseated the line, filled back up with 7-8 qrts of fluid, let it idle watching the cooler line. The line held but when putting into any gear it does not go. Just revs up. All the stories I've read of this happening to other people their transmission's are fine after putting fluid back in. Is there something else I need to do or check? Can't afford to take it to a shop to have it looked at.I let it idle with fluid filled for 25-30 minutes and the transmission got up to 207•. With my old factory radiator it stayed around 178•. Also I squeezed the top radiator hose and I could squeeze all the way to the middle. The hose was warm but not hot. Any ideas?

I will start by saying it's physically impossible for the transmission line to have just popped out on it's own IF it was previously inserted properly.
that being said it's likely if you drove it around with no fluid long enough you could have damaged the transmission bad enough that it's internally fried but really hard to say.
how far did you drive it after replacing the radiator? how many miles? if it was more than 5-10 miles you could have cooked it.
there is really no reason for it to get up to 207 just idling unless the fluid is still low or not flowing, blockage, etc.

OR VietVet · Dec 11, 2024

Maybe @NickTransmissions can chime in.

Are you absolutely sure it is full when warm and idling in Park or Neutral?

j91z28d1 · Dec 11, 2024

try jacking the rear up with the wheels off the ground let it idle in each gear for a bit. maybe see if it will shift thru some gears in drive.

if it's still topped off after that and won't move. I am not sure how but it might be hurt?

I had a line pop off a 96 blazer and it made a mess but tranny was OK afterwards. it was my fault, didn't seat right. there's also a extra safety black plastic ring that goes a round then fitting. makes sure the clip doesn't pop out I guess.

donjetman · Dec 11, 2024

May have burnt up/destroyed the pump in the tranny running it low on atf

bowtiegurl · Thursday at 3:03 AM

Doubeleive said:
I will start by saying it's physically impossible for the transmission line to have just popped out on it's own IF it was previously inserted properly.
that being said it's likely if you drove it around with no fluid long enough you could have damaged the transmission bad enough that it's internally fried but really hard to say.
how far did you drive it after replacing the radiator? how many miles? if it was more than 5-10 miles you could have cooked it.
there is really no reason for it to get up to 207 just idling unless the fluid is still low or not flowing, blockage, etc.

If the new radiator is defective, not cooling the transmission fluid down could that cause this problem? The upper radiator hose can be squeezed all the way to the middle at running temp, the lower radiator hose looks huge. My transmission got up to 238° at idle quickly today. I do have some forward motion now in 1st-Drive, no reverse feels like it's in park and neutral makes a whining noise at transmission and acts like it's in drive with forward motion. I drove a mile and a half total when pulling in my driveway that's when I saw smoke from under the hood.

bowtiegurl · Thursday at 3:05 AM

donjetman said:
May have burnt up/destroyed the pump in the tranny running it low on atf

Would a burnt up pump make a whining noise?

bowtiegurl · Thursday at 3:06 AM

j91z28d1 said:
try jacking the rear up with the wheels off the ground let it idle in each gear for a bit. maybe see if it will shift thru some gears in drive.

if it's still topped off after that and won't move. I am not sure how but it might be hurt?

I had a line pop off a 96 blazer and it made a mess but tranny was OK afterwards. it was my fault, didn't seat right. there's also a extra safety black plastic ring that goes a round then fitting. makes sure the clip doesn't pop out I guess.

Will try that tomorrow.

bowtiegurl · Thursday at 3:07 AM

OR VietVet said:
Maybe @NickTransmissions can chime in.

Are you absolutely sure it is full when warm and idling in Park or Neutral?

Yes for sure.

Transmission Cooler Line Popped Out

bowtiegurl

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swathdiver

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Doubeleive

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OR VietVet

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j91z28d1

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donjetman

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bowtiegurl

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bowtiegurl

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bowtiegurl

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bowtiegurl

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