Allison cooling lines

[gophergunner]

I have a 2006 sierra with a Duramax/Allison and it now has 103 000 km's on it. at about 25 000 km's the transmission cooling lines started leaking and were replaced under warranty. At about 55 000 km's the lines were leaking again and replaced under warranty. Now that i am off warranty they decide to start leaking on me once more. I guess my extended warranty doesn't cover this kind of stuff even though the transmission sorta needs those lines.

Anyways, each and every time they started leaking i noticed that it was always at the point where the rubber hose was crimped to the aluminum piping. (they sure look aluminum to me anyways.....correct me if i'm wrong)

I'm first of all wondering if there is any specific transmission fluid that i MUST use with my truck or does any ATF work?

Also curious if there are any companies out there who make replacement lines for these transmissions? I'd like to have it fixed for a little more than 50 000 km's at a time I know if i just get these lines replaced now, they will leak again, and again and again......i thought i gave General Motors enough money when i bought the truck:confused:

The worst thing on my truck is cold temperatures, but i let it warm up well before driving, and its just a daily driver that i don't pull anything heavy with, so i'm just thinking its crappy hoses that are the problem and not abuse of the vehicle.

[cowboywildbill]

Check with your dealer, they may still be covered for a specific time and milage from the last warranty repair. I had a trans replaced in a GM car at 98,000 under extended warranty and the trans was good for another 36,000 miles and 1 year from the 98,000 mile fix. Just a thought.

[gophergunner]

i will have to check in on that....never thought of it that way.

thanks

[More Power]

The Allison ATF cooling lines (2001 model year) I bought for Lil Red (http://www.thedieselpage.com/features/project2-16.htm) were made using steel tubing. I needed to modify them to work for this application. On three of the rubber hose/tubing connections, I needed to remove the factory crimp sleeve. In their place I used some special clamps like these from Kennedydiesel.com:

http://www.thedieselpage.com/images/jkclamps01.jpg

No leaks since.

Another possiiblity is to have a hydraulics shop install new fittings. As long as the truck is in warranty, I'd let the dealership deal with it, but if out of warranty I'd try something else for a recurring problem. I"ve not had a problem with my 2001 GMC ATF lines (7 years & 67,000 miles).

Jim

[gophergunner]

I had to drag this topic back up again, as my truck (now with 127 XXX kms on it) is still leaving puddles of transmission fluid on the ground. I have been adding to keep it topped up all the time, but this can't go on forever.

I'm off warranty, even if it was under warranty I don't think I would want another set of leaky lines installed. Anyone I ask doesn't seem to know of any aftermarket replacements for my truck either.

I have however been told, several times now, to just get some hydraulic lines made up to fit. And I was told that as long as they are cleaned out well so there is no crud from cutting the lines, then it shouldn't be a problem, people make up hoses all the time for other stuff.

I'm also going to have to make up some hose for my power steering as that one is wet all the time too.

Why can't GM get their hoses right? Last I checked GOOD hydraulic hoses on farm equipment and construction equipment use steel crimps on the hose. The transmission lines on my truck use aluminum. Last I recall, aluminum is a lot softer and in my opinion shouldn't be used for crimping pressurized lines.

Anyways, enough of my rant..... Is this a good idea to make up my own hoses for my truck or am I looking at possible damage to my transmission?

And of course its always on my mind that one day one of those leaky hose crimps is just going to give up and pop right apart and leave me stranded somewhere.

Also, would anyone happen to know the working pressure of these cooling lines? Just in case I do have some made up....

[DmaxMaverick]

If it were me, I'd just cut, flare (or possibly use compression fittings in this case) and couple the lines with Aeroquip hose fittings. Done. But, that's just me.

The operating pressure should not be more than 5-25 PSI (essentially free flow). It has a potential for over 100 PSI, but that would have to include a substantial restriction at some point. In any case, the aluminum crimps should be sufficient (up to about 500 PSI, although I'm not a fan of crimping ANY aluminum line). If they weren't, we'd hear of more than just a few failures (before or after a repair).

[tufcj]

I haven't had any leaks on the Duramax (2003, 85K miles, knock wood). I had the cooler lines replaced in my 1997 Suburban, and my wifes 2003 S10 Blazer (both while still under warranty). When the lines were done on my wife's Blazer, the service manager told me there had been at least 7 revisions to the design of the swedged line, and they still leak. You'd think the engineers could come up with something better.

Bob
tufcj

[gophergunner]

I'm still trying to decide what to do, as my leak seems to get worse every week.

But I'm curious about the fluid flow from transmission to cooler and back to the transmission. At which point does the fluid get filtered? Is it upon return from the cooler or before going to the cooler or somewhere in between?

If the fluid is filtered as it returns from the cooler then its a load off my mind as I wouldn't worry about my transmission taking a crap because I did my own hose repair and a little spec of junk got caught in there.

Sorry to keep dragging this up, but I just won't be satisfied until I don't see anymore red puddles under my truck.

[ISEEDIT]

Had a hydraulic hose made up by local CAT dealer - they used a little foam ball and compressed air to clean out the crimp/hose line. Blew it threw 2 times. That was a first for me - farm tractor dealer never did that, untill now when I tell him to start . . . .
I have my 2006 in for a tranny coolent line replacement now. I"ll be asking them about the crimp. Crimps at CAT are garrenteed, same at Farm dealership. If it blows at a crimp, good chance they will replace it for free (absent of abnormal use or abuse).