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2002 non_gmt360 other
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Discussion Starter #1
While moving my truck today so Steph ( m0stly_harmless) could put my trailer back after his out of town move, I noticed oil in my driveway. Upon further inspection I seen oil from the cover you remove to change the oil filter. I removed the plastic cover ( the bigger one that the oil filter one is attached to), and found that I had a tranny line leaking. The same as a member that posted this picture



I am going to have to replace a section of line from the tranny and remove that joint you see in teh picture and go almost to the cooler.

My question is what size is that line? Is it 3/8"? I am going to get a couple compression couplings and some steel line to replace it. Just want to confirm the size.
 

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2006 chevy trailblazer_ls
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541 Posts
many transmission coolers use rubber line. maybe you can get by using that?
 

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2002 chevy trailblazer_ltz
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68 Posts
I had transmission line rot last year. I had considered doing what some others have done, and replace the bad section with fuel grade rubber hosing. Ultimately after further inspection I found multiple sections of rot in the line, and it was going to fail soon. I brought it to the dealer and they replaced both lines for $350.

If thats the only section I would consider the rubber hosing, seems to be a great solution. Then cover the remain steel line with silicone spray!!!!
 

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2002 non_gmt360 other
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Discussion Starter #4
I just went and picked up some steel line and a few compression fittings along with a couple quarts of Dexron VI just in case and a funnel and drain pan, plus some oil for my snowblower and it was just under 70$. Now I did by 2 different lengths of tubing just in case and will return the other. Now to get motivated to crawl under the truck and get the work done.

I did consider the rubber line but when my buddy who is a certified mechanic told me that on cold startup you can easily see 200 psi+ I figured I will go steel, seeing I am replacing a few feet in one shot. I did have a tranny cooler on my previous vehicle that had the rubber line with no issues but I will try the steel line first.
 

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2002 non_gmt360 other
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Discussion Starter #5
Repair complete and it seems to be holding so far.



Here you can see the leak right at the plastic retainer


Now for the completed repair pictures





Here is what I removed


 

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2002 non_gmt360 other
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Discussion Starter #7
I've only had the truck one winter, so before that it was a US vehicle. I seen a post from another member that had the exact same problem. One line rusted and one was fine. I might have to look at some kind of undercoating very shortly.
 

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2003 chevy trailblazer_ls
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4 Posts
I believe I have the same problem...

03 Trailblazer @100k, upstate NY all it's life (plenty of salted roads for the undercarriage to contend with)

Tranny lines have been leaking gradually, but an increasing rate.. believe it's likely the same problem (rusted out trans-coolant lines) as posted here. Looks like a notorious problem with this vehicle.

My questions are

Where can I buy those replacement lines besides the dealer?
Are they model specific or can you purchase 3/8" steel or Aluminum lines and bend them yourself?
Is it counterproductive to use rubber lines rated for a certain PSI?


Great site, extremely useful with all this information posted about this truck.

Thank you ahead of time for any tips or suggestions.
:worried::weird:
 

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2002 non_gmt360 other
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Discussion Starter #10
In my case I was able to buy pieces of line and splice them together as shown in the pics. Had it been in different locations then I might have had to replace the entire line and get it from the dealer.

So far it seems to be holding up for the last 5 months. I would stay away from rubber due to the pressure in the line.
 

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2003 gmc envoy_slt
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7,190 Posts
There isn't very much pressure in the line.:m2:
 

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2006 chevy trailblazer_ls_ext
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85 Posts
I just had this work done by a mechanic I sometimes use. He actually checked other sources and could not find any other lines to use besides dealer lines, he also mentioned that the connects used at the tranny are not your typical tranny connection. I know from looking previously at the compnine site there are some kind of quick connect fittings there.
Both of my lines were very corroded, on both sides of the quick connects in the middle of the lines, so I was looking at complete line replacement. I think all parts I could have ordered on line for about $125 from the usual gm parts places. But I didn't have time to fix it myself, and I really didn't want to use the same lines from GM that sucked to begin with. :hissy:

So he ended up cutting the lines about 6 inches from either end, and replacing them with compression fittings and copper lines. Works for me!
 

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2002 chevy trailblazer_ls
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1,433 Posts
I've got the new GM lines. Surprises me that they aren't coated or anything to resist rust :rolleyes: When I go to put them on I think I'm going to paint them, except for right at the fittings. Then once it is all put together, paint over the joints to seal it up. Unless there is a better way, or painting the whole line end to end wouldn't affect it sealing.
 

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2003 chevy trailblazer_ltz
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15 Posts
Clean the lines good and put a couple coats of linseed oil on them. We live up here in north east ohio where the roads are practically made of salt during the long winter. My grandpa has a 88 chevy pickup that he undercoated with linseed oil 5 years in a row and it has no body rust, and has never had any brake or trans lines replaced. It also has 250,000 miles on it.
 

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2003 chevy trailblazer_lt_ext
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140 Posts
Well yesterday morning i discovered a large amount of oil on my driveway. Didn't think much about because i have 1994 Tbird that has a rear main oil leak. I went to clean it up it was not motor oil. The first picture is what my truck looked like. Now at a local shop its going to cost just shy of 500.00 because he's replacing the four lines that are used in the trans cooler. BTW he tells me that GM has a tsb out because of the corroding lines.....Also I'm having a trans flush done. Looking at the fluid on the drive it was dark brown. I was about 50k is when i had it done last.This is why i did not think twice that maybe it was not the truck. Just a heads up to all that these line WILL CORRODE and you don't want to blow up the trans.
 

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2006 chevy trailblazer_ls
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1 Posts
Transmission cooler line pressure????

There isn't very much pressure in the line.:m2:
What is the Pressure? I am replacing the lines, and want to know what grade and rating hose to get.
Stupid thing blew on my daughter midnight in the middle of nowhere last night.. got the rot cut out already, and compression fittings with barbs, added some rubber line. Just want to make sure of the pressure before I send my wife off to work in her trailblazer....

Thanks everyone.
 

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2004 chevy trailblazer_ls
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333 Posts
I just went and picked up some steel line and a few compression fittings along with a couple quarts of Dexron VI just in case and a funnel and drain pan, plus some oil for my snowblower and it was just under 70$. Now I did by 2 different lengths of tubing just in case and will return the other. Now to get motivated to crawl under the truck and get the work done.

I did consider the rubber line but when my buddy who is a certified mechanic told me that on cold startup you can easily see 200 psi+ I figured I will go steel, seeing I am replacing a few feet in one shot. I did have a tranny cooler on my previous vehicle that had the rubber line with no issues but I will try the steel line first.


I did the same thing except I used flair fittings. The line I used was steel brake line.
Been fine for about 2 yrs. survived a trip from NJ to Utah and back.
 

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2002 gmc envoy_slt_xl
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86 Posts
I just wanted to let you guys know. My 02 envoy xl 4x4 had 1 trans line starting to leak and loose alot of trans fluid on my 25 mile round trips.
I couldnt redneck repair it due to the leak being above the rack pinion area.
So I took it to my local shop I TRUST. To replace all 4 lines and fittings and add fluid etc other fees and tax was $277 out the door. The labor shown 2 hours worth at $130.

I thought it would have taken much longer to do.

Very Happy with my local shop.
 
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