The Dreaded Transmission cooling line leak "Help"!

[cowboywildbill]

Well, I was checking and prepping our truck and trailer for our yearly trip to the
All American Quarter Horse Congress in Columbas, OH. It's about 450 miles each way for us.
There are some pretty long steep grades on the way out on route 68. So it does work the truck pulling 40 ft. of trailer.
After doing the tires and checking the fluids I looked under the truck and there was a little trans fluid under passenger side front just aft of the radiator on the plastic skid plate.
I also noted a very small spot on the pavement under the truck. After looking around I also found a couple of small spots where I had parked before. We are on a small Ranch so I didn't notice the spots before, you know with farm machinery and such. Fluid level was OK and where it should be. So apparently it had been leaking for a while.
Is this thing safe to run on my trip if I keep a close eye on the fluid level? I'm hoping the leaks on these lines stay small and don't let loose and cause a sudden loss of fluid?
What has been your experiances with these leaks? Our truck is an 07 classic with only 21,000 miles on it. I'm hoping this is covered under warranty. I'm sure it takes a while for the Dealers to get the lines from GM. Thanks in advance.

[gophergunner]

I have a 2006 Sierra and I went through the same great fun......about 4 times!!!

I bought a new set of hoses that were supposed to be new and improved, so I was hoping it would solve the problem. Well, I was all set to replace them and after seeing I needed to remove my winch, bumper, grill guard and then the truck bumper I got mad and cute the tubes right next to the hoses and just put on my own compression fittings with hydraulic hoses.

I figure if they work on farm equipment with 3000 psi, they will work on a pickup truck transmission.

a little over 10 000 km's on them now and not a problem at all. No leaks and everything is still tight.

[cowboywildbill]

Thanks Gophergunner, Do you think I'll be safe to run untill I can fix it? I'm guessing they just leak slowly.

[JohnC]

As long as they don't pop apart like the oil cooler lines...

Good news, they're lower pressure. (I think...)

[gophergunner]

I do not know the pressure on the lines, but I'm not thinking its very high. When I was solving my problem, I disconnected the lines from the transmission and all that seals these connectors is an O-ring and a spring clip to hold the line in place.

It's the type of connection that you could spin around all day long even when they are properly connected. Doesn't seem like a high-pressure connection of any sort.

About the leaky lines and driving though.....well in 2008 I had one of the situations, and I had to drive an hour from home to go to school. When I was at home the lines were wet, and were leaving drops all over the place where I would park, but after I drove to school the underside of my truck was wet with tranny fluid.

So they can start leaking more, as your driving, and if your going a long ways, towing and not checking I'm thinking it could be trouble.

[2tough2park]

That location sounds like the exact same place I found a "small red puddle" on the driveway. One cooler line connecting to the cooler itself had started leaking at the soft line/hard line connection in the exact spot you can't get to. I think it was a $250 replacement cost at the dealer as I wasn't f'ing with it because it was so difficult to get to. I didn't want a stock replacement line, but I didn't have much choice at the time. And no, it wasn't covered under the 100k mile powertrain warranty. Funny thought about that..........
So the tranny cooler line fails, tranny fluid dumps everywhere, the tranny goes dry, the tranny burns up and fails. BUT, because the tranny cooler line is NOT part of the 100k mile powertrain warranty, your replacement tranny won't be either. Don't believe me? Ask Radley Chevrolet. I did.
Being the way I am, I'd get the line replaced before you leave.

[conway]

Interesting how different dealers handle problems. My dealer covered the transmission lines under warranty on my 2007 classic. It actually showed up just before 36,000 miles in the form of transmission shifting problems that was traced by the dealer to low transmission fluid. They topped it off and sent me on my way. Happened one other time and then I noticed fluid on the pavement where I work. Took it to the dealer and the suggested that he check for the leaking lines since it was showing up regularly on this forum, even though I am not in to cold a climate (it does sometimes get down into the 50's but I try to stay under the covers on those days). It was the lines and the service manager said it would not be covered since it was now over 36,000 miles. I suggested that maybe his incompetent mechanic failed to find it on the original go around and he basically said 'tough'; I thought to myself that this is certainly a reason not to use their repair services but before I could leave a service writer came out and told me that it is covered under the 100,000 mile warranty. I asked for the old lines so that I could use it as a template for 'proper' line that I would make up if it happened again but was told that the lines needed to be shipped back to GMC for warranty verification. Go figure.

[gophergunner]

They always told me the lines had to be returned for warranty, so once I had to pay for a set that wasn't covered by warranty, I asked for the old leaky lines and they were given to me!

Next time I'm home I might just need an oil change, so I might possible be able to snap a picture of how my lines look now.

[cowboywildbill]

I traded it in on a new 2011 3500 D/Max C/C LTZ.
So someone else will be fixing them. "Ha Ha"
After towing for 450 miles and checking it, it didn't appear to be leaking anymore.
I'm wondering if when they heat up they don't leak as bad. It was just barely leaking before. Just enough to leave a little spot.? "Oh Well"