trans line leak

[digglesworth]

So while doing all the recent work under my truck, I noticed a leak from one of the trans lines between the trans and cooler. It seems like it's one of the crimped ends of the short rubber line that connects the hard lines from the trans to the hard lines from the cooler? Can I have a shop re-crimp those fittings or do I just need to have those little hoses replaced? I have a transmission shop like a block away from me. I might drop the front skid and have them take a look.

 

[SuperBuickGuy]

the expensive way is to replace the lines, or remove them (not even sure that's possible with the motor in) and have new rubber crimped in, or get an AN flaring tool, AN fittings and some braided line and fix it yourself

 

[digglesworth]

What is this AN you speak of? Cmon Google, don't fail me now.....
I wanna see if I can get it replaced fairly inexpensive. If I gotta cut lines myself, ill look into cuttin the rubber sections out. I'll have to cut em on the trans side, flare em and just hook up new line to an aftermarket cooler... I wanted to tie on to the fittings that plug into the cooler so i could re-use them if I had to but this leak may have made the decision for me.

 

[rsc]

AN=Army/Navy. Its a government standard that parts/pieces are made too. I believe that you would cut the metal lines from the transmisstion as close to the crimp/flare as possible, flare the tubing for the appropriat hose and fitting and crimp tight, good as new. That will give you a new hose to connect to the radiator/cooler. If you are leaking from the fittings on the radiator you might be out of luck unless you can keep the fitting from rotating while you tighten the jamnut. Do not let it drop back down into the radiator tank, that brings on the suck.

 

[digglesworth]

Thanks for the knowledge... I'm gonna go the bypass route. I ordered a cooler and thermal bypass valve... It's leaking from one of those crimped ends on the trans side. I'm gonna pull those crimps, flare those ends and run new hose to the external cooler. Hopefully killing two birds with one stone.

 

[alrock]

I believe this is where he's cutting/flaring

 

[poncho1965]

So, you cut off the crimp and your pic shows what you would see?


Mike

 

[alrock]

Correct. And then Reloader put a flare on the ends to fortify the sealing in the rubber line, with the fuel line clamps in the middle.

 

[alrock]

He cut one side with a saw and tore it open with a screwdriver. From there the metal peels/falls off and the hose just pulls off.

 

[digglesworth]

That's where I got the idea to splice it.

 

[Reloader]

I have repaired many of these lines on GM vehicles over the years like this. It's real common on Both the trans and the engine oil cooler lines if equipped. The engine oil lines are much easier than the trans lines to replace so we would replace them but the trans ones are a bitch due to their length and tightness of bell housing to tunnel. The line sets are cheap and the after market is making them for many applications. I've seen them for way less than a c-note from company's like Dorman. But they are a pain in the butt to replace especially if you are working on the ground.
When cutting off the aluminum crimp just be carefully not to nick the rib on the steel tube that positions the crimped piece. Just saw through the flat part over the rubber hose and force open with a screwdriver like in the pics. I use one of those hack saw blade holders that allow the blade to stick out of the handle. The rest of the aluminum crimped piece will tear open and you can remove it. When flaring the end ,you just want to bulge it a bit so set up your double flare tool like you are going to do an inverted double flare and just bulge the end of the pipe a bit so it looks like the ones on your new oil cooler (unless you have one with threaded connections). Position your fuel injection hose clamps on the line so you can easily check them for tightness with a nut driver occasionally. Don't forget to use only trans oil line as oil does attack rubber and soften it. If you check my old thread on steering rack bypass hoses there are some good pics of the line bulges I'm talking about. It's on page 32 of the Hummer H3 section of the forum.

 

[digglesworth]

Your directions are top notch Reloader. I got my rear axle seals taken care of with absolutely no problems with the directions you sent me. I owe you big time. I just went and bought a flaring tool so Ill have to familiarize myself with some of the techniques. I watched a YouTube video on how to do a bubble flare using the flat part of the bar and the adapter that comes with the kit. I'm using the hose that comes with the kit and I also purchased an extra hose from the same company so I have plenty. I plan on making the caps everyone makes out of the fittings for the stock cooler. I'm gonna leave an inch or two sticking out of the stock cooler, flare those ends and stick some rubber caps on them. Depending on how much extra hose I have left, I may cut two pieces to use as new pieces to the stock cooler. That way if anything ever happens with the ext cooler I can throw those short pieces in back to the stock cooler in a pinch. I'm gonna look up that thread. I've been trying to find info about the jumper used to bypass the rack so you don't burn up the PS pump. That'd be nice to throw in the trail kit too.

 

[digglesworth]

and I just had a trans flush a few thousand miles ago. im gonna drain as much of the un-contaminated fluid as I can into a jug. ill probaly have to pick a qt or so to make up the difference.

 

[jphh20]

This is a great discussion, I have the same leak starting to weep. Thanks for posting the pics which provided a better understanding how to disassemble the lines and work the bi-pass. Does anyone have a recommended trans cooler that mounts easier than others?


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[alrock]

The key thing is picking a cooler with enough cooling ability. If you read into a lot of the coolers, they are meant to be used in series with the existing one and not necessarily serve as a replacement. Go up a model or two. I decided that I wanted something with at least 20,000 BTUs max cooling, or one for roughly 24,000 GVWR (the other way they seem to to measure it. I have a thread of my install in the Tech Library.

 

[Reloader]

I recommend mounting it like Alrock and I did ours. Zip tieing it to the condenser is not the way to go in my opinion. A condenser is vulnerable enough as it is without adding more weight to it. best to have it supported by the core support . The cooler Alrock got I thought was a good size and fit the right side very well. you just need to be a little creative making the brackets. We used the ones in the cooler kit. The make and model should be in his thread about it. No fancy tools were needed other than a double flare kit to bulge the lines to retain the hoses better. I used a small drill press vise to bend the brackets.

 

[digglesworth]

I've got a derale 13503 on the way. It's supposedly rated at 22000 GVW. Not sure the BTUs on it. I hope it's big enough. I also got a tru-cool thermal bypass valve to put inline to help the transmission warm up before it starts cycling fluid to the cooler. I live in the Midwest so temps drop pretty low. Without the valve, it would take forever for the trans to warm up, if it ever did.

 

[alrock]

Understand the desire for the bypass. The ones we put in supposedly address the warming up with Low Pressure Drop (LPD), where thicker ATF doesn't go through the fins of the cooler thus allowing a quicker warm up. If I were in a cold area I might put in the bypass. I haven't seen any comparisons online showing if LPD is effective or not.

 

[jphh20]

Good point on the LPD and colder climates. I too will need an application here in CT as winters can be pretty cold and I tend to go up North often. Let us know how the bypass with LPD goes.


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[digglesworth]

Temps here around st. louis can get rather bitter in the winter. That's why I decided on the bypass valve. I think I'm gonna mount it on the crossmember next to where the drivers side rack bolt comes through. That valve won't let fluid through to the cooler until 180 degrees. Even with the fluid not cycling "through" the cooler, just running out to it and back would yield some cooling from air hitting the lines and the top row of the cooler where the thicker oil is "passing through"... Put a 40mph wind chill on that and there's gonna be some cooling. Not as much as if it was cycling through the whole cooler but some. You guys in warmer climates sure have it made.... Lol. The amount of cooling that would yield by just running through the top row of the cooler is probably insignificant because you guys don't have to worry about frigid temps as much or hardly at all. So for me, I don't want fluid to even reach the cooler till it's somewhat warm. With the skid plates and stuff. The transmission is somewhat blocked from the wind. But who knows. These mods everyone comes up with are all matters of opinion... It just so happens the work. And work good. Too bad GM didn't put this much effort into engineering. I feel like my truck has become more capable and more reliable with the help of this forum and it's members and I'm grateful. Ok. Rants over.

 

[Reloader]

What you mean we gots it made. its only gonna get to like 68 degrees today. And there are some clouds in the sky.

 

[chaos254]

Bypass valve just seems like another thing that could possibly fail. Without having a temp gauge I would be wondering if it was in fact working correctly.

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[digglesworth]

I'll will be investing in a scangauge II soon. That way I'll be able to monitor trans temps among other things. It's all a matter of trial and error at this point. If it doesn't work, I can always hook up the stock cooler. If you don't like the bypass valve, don't use one. Your transmission will just take longer to warm up...

 

[poncho1965]

Bypass valve just seems like another thing that could possibly fail. Without having a temp gauge I would be wondering if it was in fact working correctly.

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I have a Scangauge to monitor my temp. By pass valve is just like the coolant thermostat. Spring loaded. Open when cold, closes when hot to put all flow through the cooler. We've had a low of 15 degrees here so glad I installed it. Tranny shops opinion was that it is probably not needed.


Mike

 

[digglesworth]

Which cooler did you go with mike?