I replaced leaking transmission fluid cooling lines on a 2008 Impala LTZ that I purchased new. It was NOT the 9C1 model. Mine had (as most do) the transmission fluid cooler tank in the right side of the radiator. The transmission lines began to slowly weep where the rubber portion was crimped to the metal (aluminum) lines. It had the 3.9L V-6 and the 4-speed automatic transmission.

The lines were released with a “quick-release” tool, but required a separate, small fitting that was inserted into the radiator, before the end of the lines were snapped in.

You may want to go to a GM dealer with your VIN, to determine exactly what lines are required - and if any special fittings are needed.

I THINK some 9C1 models had an external transmission fluid cooling radiator, placed in front of the coolant radiator and a/c condenser. You could examine your vehicle to determine if you vehicle has this separate cooler.

 

The quick disconnects are JiffyTite oil cooler fittings. The tooling is available to form the ends on steel line. The replacement fittings in the radiator and transmission have O-rings to seal on the formed end of the lines.

You can cut off the crimp ferrules and install new 3/8" SAE J1019 hose with Oetiker Clamps, German Fuel Injection Clamps, or Rotor Clip Constant Tension Band Clamps.

Don't use worm clamps on smaller diameter hose. They don't clamp evenly and the hose extrudes through the worm slots and loosens up fairly quickly.

Oetiker clamps will likely eventually loosen up just like the original crimp ferrules but they're cheap, clamp evenly, are easily replaceable, and they will last several years.

Fuel Injection clamps are inexpensive, work as well as Oetiker clamps, and can be tightened and re-used if needed.

Rotor clip clamps will maintain even tension over temperature changes, can be re-used, and again are fairly inexpensive. The reason I recommend the Rotor Clip brand is their bands are made of heavier spring steel than the knockoffs.

 

If you wish to look at a GM parts listing and diagram to help you figure out what the lines should be like on your vehicle, try going to one of several online GM parts store/dealer websites. One you can try is www.gmpartsdirect.com and select from your model year, make, model, package, engine, etc. I find that the "police" selection sometimes doesn't give me a full list, when that happens, back out to the "LT" or "3.9L" selections and look there. You can also order the parts there if you wish, and they do answer your email questions within a business day or so. They guarantee whatever parts they quote you via email will fit your vehicle or take it back if it doesn't. Luckily mine just had surface rust without leaks, so I cleaned/sanded them some and painted them (while on the vehicle) with Rustoleum rust converter primer and then their gloss/satin black paint to try to make them last longer. Good luck.

 

I would also replace the fittings as well. As easy as they are to get to, and as cheap as they are... Just replace them.

https://youtu.be/_TLUXUQjU_4

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