In the last few days I've noticed a small leak appearing underneath my truck. The fluid appears red in color, but doesn't have any distinct smell. It got dark on me so I didn't get a chance to remove any of the skid plates or get really good pictures. Hopefully someone can identify this.

What you're looking at is a picture from underneath the front passenger side of the vehicle looking back and slightly up. The camera is positioned underneath the radiator but in front of the engine. You can see the bottom of the serpentine belt's path for a point of reference. The hose from the camera's angle appears to travel back towards the rear of the engine. In the other direction, it appears to travel up, possibly to the radiator area.

I've marked the fitting on the hose that appears to have the most fresh fluid. I'm not sure if this is the point of the leak, as the entire hose in that general area is oily from the leak.

http://www.opentabentertainment.com/truck/hose_leak.jpg

I would put my money on the trans cooler lines.

I would put my money on the trans cooler lines.

Yep. Mine are leaking as well.

Well that sucks. Since posting this a few hours ago I've read a lot on the tranny cooler lines leaking, but have not found a general concensus for the fix. I don't see a TSB or recall for this yet. Has GM released some updated lines that won't leak again after a few thousand miles or is there a proven aftermarket replacement?

i just bought a Certified Pre Owned, last friday(11-27). and today (sunday12-06) had to drop it at the dealership because of leaky tranny lines.....

The hose they used feels like cheap plastic garden hose. You can't clamp or crimp that stuff for nothing. The new lines seem to be made of exactly the same stuff. If it were me I would get some oil cooler hose, cut the crimps off and slip the old hose off, slide the new good hose over the ribbed portion of the steel line and double clamp it.

welcome to the club!

4th sets for me so far

youd think by now someone would be producing a decent aftermarket line for everyone to buy............for all you guys that are having the dealer fix it every time, are they giving you any trouble about it, especially if you have a lift kit or some serious mods done?

A question to you guys who have this repaired multiple times: Is presenting the TSB to the service department at your dealership enough to get it done and get it covered by GM?

Brand new to this forum. I just noticed the same thing on my '06 yesterday. Does anyone know how much pressure is on these lines?

Crap. Not only do I have the pump rub issue to look forward to but now this....

Most of the time this is a issue for northern trucks from the cold weather. Stakeman has posted the best fix I have seen in the Trans section

Brand new to this forum. I just noticed the same thing on my '06 yesterday. Does anyone know how much pressure is on these lines?
According to the gauges on the BG flush machine, about 40-60 psi. Not a lot but enough you need to use some good quality hose. I used transmission cooler hose when I had to redo the lines for my 4L80E. IIRC its rated for 150 psi. Its not cheap but neither is a new 4L80E or in your guys case a new Allison.

this is so bogus! it happens every year when it gets cold, i can't believe there isn't a better hose available yet. i wonder why the general is tanking? a couple lousy hoses they had made in mexico to save $$$ aren't holding up and their "long term" fix is to replace them with more of the same- if i open up another "genuine gm" part and see "made in mexico" on it, i'm gonna lose it!

if i open up another "genuine gm" part and see "made in mexico" on it, i'm gonna lose it!

si seņor.....
JK.:D

Well I went to the dealer prepared with TSB in hand and told them that the lower trans cooler line was leaking at the crimp and they acted like they had never heard of this before. Now, being in south Louisiana, I suppose there could be some validity to their response. But all they were happy to help with was the quote on what it would cost me to have it repaired. I walked over to parts to get a price on the hose (they actually had it in stock, which tells me they've replaced them before), then walked out empty handed.

There is an auto parts store in town that makes custom hoses, so I'm going to bring them mine and hopefully have them replace the hose and crimps.

I just purchased my first diesel pickup and I've noticed the same thing under my rig. Does it hurt anything to let it leak like this?

It could eventually fail in which case you will pump all of the ATF out of your trans in about 10 seconds.

Hey Dozer..thanx for the plug.! (should be in business making these things..hmmmm..??)

Guys - check this out. And keep in mind, it is the crimps that are the issue - THEY WILL Leak. No question. get a new set under warranty - fix em. Get a new set under warranty and have GM install them.?, garanteed they will leak again. I went through 2 sets before going out of warranty.

Got fed up and here was my solution.

http://www.dieselplace.com/forum/showthread.php?t=290336

the other massive thread is this one: 800 posts..

http://www.dieselplace.com/forum/showthread.php?t=202078

cheers,

stk

If you did I'd buy a set. There is a guy on here who has a lower set on ebay for $149 plus shipping. Does that sound high to you? I can buy a set from GM for $43 and I'm would think I could get the local hose shop to put new crimps for less than $100. I could be wrong though.

I don't think the ebay is a set, just the lower single line (one that leaks most).

its those stupid tranny cooler lines

I just quoted out a set this week. Roughly $34-48 a piece for the two main lines that leak. We have a place here called Tubes 'n Hoses. Guy I knew had an S-10 that seized the engine when his oil cooler lines blew. Took his hoses to those guys and replaced the aluminum clamps with steel. Flawless so far.

I never had this problem with my 2002, but when I bought my 06 the lines were leaking made the dealer fix them before I would take the truck and now it looks like I'll have to do this over down the road?

I fixed mine..... Went to Greenline hose and fitting in Edmonton, Alberta...... Cost me $120 CAD for these good fittings and hoses...... did it over a year ago and haven't seen a drop of fluid since....
http://photos-a.ak.fbcdn.net/hphotos-ak-snc3/hs090.snc3/15764_362904160354_590115354_10129925_5316887_n.jp g
http://photos-c.ak.fbcdn.net/hphotos-ak-snc3/hs090.snc3/15764_362904165354_590115354_10129926_8340141_n.jp g

I should mention that was all three lines I did for $120.....

my 06 leaks like a siv out of lines havent taken it in yet, dont know if dealer will cover it or not

Thats a killer setup for 120 cad! What type of end connectors did you use?

well i'm not sure what they're called exactly but they're sort of a bite type fitting where you have a nut a little brass ring and then the actual end of the hose.... so you slide the aluminum tube from your trans line in and then tighten the shit out of it and it squishes that little ring to seal the lines.... the hoses are hydraulic hoses i'm pretty sure.... basically i just went to a hose and fitting place.... said this is what i have this is what it's on this is what i need it to do... and a half an hour later he had that built for me

I had better look @ my cooler lines. I haven't noticed any leaks. w/44.5k on the clock, is it too early?
What mileage have your '06s been having when you noticed the leaks?

I was trying to figure out a build sheet to get some made. Im not sure how long they need to be or what to even use. I would take them off but I need my rig running.

I had better look @ my cooler lines. I haven't noticed any leaks. w/44.5k on the clock, is it too early?
What mileage have your '06s been having when you noticed the leaks?

Mine started leaking at about 16K miles. I am on my third set at 29K miles now... Mine is an 06 as well...

i just put my truck in the shop..... took all 3 lines off went into the hose and fitting shop..... he looked at them and just fabbed up what i needed.... did the whole process in a half a day or less....

I went to my dealer today and they said GM came out with a new style of crimp for the hoses. He insured me they wont be leaking with this "new" style, we shall see.

..I went to my dealer today and they said GM came out with a new style of crimp for the hoses. He insured me they wont be leaking with this "new" style, we shall see..

I can pretty much garantee they will in fact leak. If the crimps are Aluminum...LEAK they will. Ya see the lines are steel, the crimps are Aluminum...theres the issue..its a combination of different abilities to absorb and conduct heat - expansion and contraction and corrosion. (Different metals in intimate contact will set up a corrosion cell).

Get em fixed the right way and never look back....besides you may have TC pump rub issues coming soon ~ 75,000miles and up it can happen.

Cheers,

stk

According to the gauges on the BG flush machine, about 40-60 psi. Not a lot but enough you need to use some good quality hose. I used transmission cooler hose when I had to redo the lines for my 4L80E. IIRC its rated for 150 psi. Its not cheap but neither is a new 4L80E or in your guys case a new Allison.

In cold weather (which tends to cause the leaking problem), you can see well over 200# pressure in these lines on the Allison. Heymcall has posted that he uses high pressure hose and compression fittings to repair them on the truck. A switch to a TES 295 fluid will lessen the cold weather pressure in the lines. DEX VI does not flow well, or at all, in very cold temperatures. IMHO, Crazycarl has the right idea — others have done the same thing.

http://www.dieselplace.com/forum/showthread.php?t=340309

My '06 had it done at 22K. They made me remove the snowplow mount before they would do it under warranty. Apparently the 15 minutes required to unbolt and reattach the plow mount was too much trouble for them to throw into the deal. I noticed the new lines leaking just a tiny bit again at 26K and I'm monitoring it closely for it to get worse. I'm up to 29K now. I agree with previous posts that the REAL fix is custom made hydraulic hoses, not those flimsy Mexican jobs that the factory uses.

So I got a new lower tranny line today, with intentions to bring it straight to my local hose shop to have the crimps redone, when my eyes spotted a red Maple leaf... Upon closer inspection, my doubts were confirmed when I read "Made in Canada". With all the talk of these crappy hoses being made in Mexico, has anyone had luck with the Canadian-made versions? I may forego the hose shop and give these a try, unless I hear that these are having the same problemes.

I had two set of lines done under my warranty but now under extended warranty the dealer said nope "They're a maintanance item now" So i took off the lines went to local hydraulic house and got 3 new "hydraulic lines" to replace the original rubber crimped ones. Cut 1 line at a time with a sawzall, put on fitting and flared the aluminum line then installed them on the truck in pieces then put in new replacement hydraulic lines and now they're good. Putting them back together in pieces made it easy to get them back in instead of twisting and turning and raming them in. Cost me $50 for the three 8 to 12 inch replacements and the fittings. Oh and a whole days work.:cussing:But no more leaks.):h

So I got a new lower tranny line today, with intentions to bring it straight to my local hose shop to have the crimps redone, when my eyes spotted a red Maple leaf... Upon closer inspection, my doubts were confirmed when I read "Made in Canada". With all the talk of these crappy hoses being made in Mexico, has anyone had luck with the Canadian-made versions? I may forego the hose shop and give these a try, unless I hear that these are having the same problemes.

why did you buy the whole line? just take you old one off and into a hydraulic shop. probly save yah $40. i looked at a made in canada set today at a dealer. i dont trust them.

why did you buy the whole line? just take you old one off and into a hydraulic shop. probly save yah $40. i looked at a made in canada set today at a dealer. i dont trust them.

Because I can't afford for my truck to be down for several days while I take the existing lines off and have them repaired, then put them back on.

fair enough, but it wouldnt take days to do this. maybe 4 hours tops. just an idea.

Not being familiar with what I'm doing, I have a feeling it would take a half day for me to get the lines off, then a day to get them done, then another half day to put them on. From what I've ready they aren't exactly easy to get to, and bringing them to the dealer is out of the question.

yah probly good call on your part

Those stupid lines leak all the time - I am on my 3rd set. They just come with the territory.

i started reading this and wondered why someone has not come out with a set like steakman and his SSteel braided with a teflon inner coating. The nuts on the tubing were Silver soldered. thats just mine own thinking though