Trans Cooler Line

norsemanberg · January 21, 2009

I was attaching some new hardware under my truck on Monday and i noticed one of my trany cooler lines was wet and it had a drop of trans fluid forming ( for military personal it is a Class 2 leak ). It looks like there is some strange fittings connecting the line to the trans and to the trans cooler out front, whats the deal how do they come off of there?

gave20 · January 21, 2009

Good luck, it's about a 3 hour job and a huge bitch. I read some other write-ups and looked at what all was involved and gave up. Mine leak, if you replace the liens with GM ones they'll leak again. To me it wasn't worth the headache.

By the way you'll need this

Here's a write-up on the fun: link

2500HD 8.1 · January 27, 2009

Has anyone else had this problem? I just noticed that the trans cooler line has a slow leak on my 04 Avalanche and is leaking from the fitting. During the summer the oil cooler line on my 05 Denali did the same, but it seemed to stop.

Is this a common problem or design flaw with these lines? I just bought the Avalanche a month ago/600 miles ago (currently has 91K miles), and I drained the trans pan and added 3 or 4 quarts of Dexron VI. I was just wondering if the synthetic trans fluid could have loosen things up or seeped out of a seal?

2500HD 8.1 · January 28, 2009

Anyone see this problem before?

gave20 · January 28, 2009

Common problem, ha that's laughable, it's been a problem since the mid 80's and GM won't switch POS suppliers. You can replace the lines but as soon as it gets cold again the aluminum fitting shrinks and starts leaking again. The only way to permanently fix the lines is to put a homemade fitting on the lines. Read these links to learn all about these shitty lines.

link

fix

jvmorgan · January 28, 2009

Thanks for posting this information I was looking into purchasing a tranny cooler since I just got an enclosed trailer to haul my hunting stuff in and I was looking into getting one at the dealership. Has anyone had the same problem with the aftermarket kits or universal coolers by other companies such as B&M or is this just a common problem all around?

Justin