Leaking trans cooler lines

deadguy

New member
For all you old 3.8 auto guys has anybody fixed the leaky cooler lines with anything. Mine are starting to drip. Wondering other than replacing the entire lines what my options are
 

ScoobyCarolanNC

Caught the Bug
It was a total pain in the ass, but I replaced the lines completely on a Sunday in my driveway. The previous owner had cut the factor rubber off and did a poor job replacing it so I wanted to start over from scratch. Advance Auto has a Dorman version for $125. They're having a big online sale right now if you use the code REBATE for tax season. No special tools or anything besides a pick to pull the clips off the quick release fittings. She'll loose about a quart of ATF+4 when you take them off so have that ready.

There's a YouTube video of a guy who cuts the fittings off and uses hose clamps, but for the amount of time it takes just replace the whole thing. I noticed in several video that guys who repaired them still had leaks. If you watch the Mishimoto Trans Cooler install video close, theirs are still leaking.
 

jeeeep

Active Member
I did both, cut the hose off and used transmission cooler line + clamps to fix it and then replaced it once the new lines arrived.

Here's what I discovered, the old leaky lines are 3/8" on 5/16 tubing with no barbs to hold the hose, it relies 100% on the factory crimped clamp. with the hose too big for the fitting it won't seal. when I cut the crimp off the line slid off without any effort.
I bought new 3/8 line just to test and it did the same thing as factory - slid on and off the fitting with no effort.

I bought some Hayden 11/32 hose, and had to cut the steel lines just before the flair then ran the hose at least 3-4 inches and put clamps on it. it stopped the leak but looked like shit.

the best price I found for factory lines is from stevewhiteparts.com.

the new lines still use 3/8" hose but they've put a flare on the end of the steel line so the hose fits tighter and crimps better, time will tell if it'll leak again.

putting them in took me just over an hour. the line are on with quick disconnect clips held on by spring clips. when you remove the clips pay attention which way they came off, you'll need to install them the same way to get the plastic retainer cap to fit.

if you raise the driver side (front and rear) so it leans to passenger side you won't lose as much transmission fluid. have something to catch the leaking fluid from the transmission fittings.

remove all the clips then slide the whole assembly to the rear to get the front of the lines clear of the suspension - pay attention which way they are routed over the drag link and track bar!

once the front is clear of the suspension slide it all the way forward and you can twist the rear fittings to slide out.

reverse to install, get the rear line in place , do not connect them as you need to slide them back to work the front of the lines into place.

Once the lines are in place install the clips and snap the caps on.

check your trans fluid level and add fluid to replace what came out.

Good lick :thumb:
 

ScoobyCarolanNC

Caught the Bug
I'll add that the upper tranny side connector is near the shift cable. Be careful, but you may need to use a tiny bit of force to get it out & back in.
 

deadguy

New member
Are they making any lines that Incorporate a aux cooler or do you still have to hack the rubber lines up to plumb one in?
 

Easy843

New member
So mine were dripping pretty bad as well as you can see and I actually removed both lines and took them down to a rubber/hose shop and they hooked me up with this set up. Its just a more assuring permanent fix that works great in the cold up here in AK. ImageUploadedByWAYALIFE1457982381.977752.jpg ImageUploadedByWAYALIFE1457982440.083924.jpg
 

RoubsX2

New member
Assuming you're leaking at the rubber hoses, you can use a dremel and carefully cut off the crimps to separate the hose from the hard line. Then just use fuel injection hose clamps (not regular hose clamps) to clamp the hose back to the hard line. I've used this technique to add B&M trans cooler connections to my rig.

Here's a video example I've found showing this technique:
4 part video -- part 1 of 4: https://www.youtube.com/watch?v=wKp638KdnuQ
 

ScoobyCarolanNC

Caught the Bug
This video is why you just replace the whole thing. After he said it took like 20 minutes a fitting to cut & peel them I said forget it. To each their own, but I'm a one and done guy.
 
So mine were dripping pretty bad as well as you can see and I actually removed both lines and took them down to a rubber/hose shop and they hooked me up with this set up. Its just a more assuring permanent fix that works great in the cold up here in AK. View attachment 192902 View attachment 192903

Nice upgrade!!!!

I went with OEM replacements, but kept my old lines to cut the crimps off and replace the rubber lines....a good project for a rainy day I guess.
 

jeeeep

Active Member
when cutting the crimps off be very careful not to knick the raised lip it covers, if you knick it they will leak - even the smallest knick, ask me how I know...

also use some 11/32 trans cooler hose, the 3/8" hose they use is too big for the fitting which is why they leak to begin with.

my lines had been leaking slow for years but it got worse, bad enough I was leaving a puddle.

Had my lines arrived sooner I would have saved hours. I should have just cut the tubing off behind the crimps and push about 3" of 11/32" hose on the straight tube and clamped it - that's what I ended up doing while I waited for my new lines.

took me about an hour to install the new factory lines :naw:
 

sherfjeep

New member
It’s my understanding that if you replace with stock lines they will eventually just leak again. I don’t understand why you couldn’t just add compression fittings and barb adapters. With new rubber lines.


Sent from my iPad using WAYALIFE mobile app
 

jeeeep

Active Member
It’s my understanding that if you replace with stock lines they will eventually just leak again. I don’t understand why you couldn’t just add compression fittings and barb adapters. With new rubber lines.


Sent from my iPad using WAYALIFE mobile app

they redesigned the new lines with the smaller hose that actually fits properly.

It's also a recall item because of the faulty design
 
Yesssssssssss. That's what I'll do next time.
Nice fix. My 08 had the same issue, 130,00km the dealer fixed mine, on my dime. I was just outside the extended warranty coverage....Nice! I kept the old lines with the intent of cutting off the crimps and rebuilding. But then I ended up with a newer jeep.

Still have the old lines....free to good home for a local jeeper.
 

jeeeep

Active Member
I’ll check on that. But unfortunately mine is out of warranty.

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it's not...when I first inquired I was told mine was out of warranty and the mileage.

I was talking to Chrysler customer service about the spring clock issue and we got on the subject of transmission cooler lines and the person I spoke to told me I was in fact covered since it was a recall item.

I had already purchased and installed the line but they reimbursed me in full.
 

ImLost7

New member
Just replaced my weeping lines (my hose replacement attempt failed) and now I have a leak at the lower fitting on the transmission side. The good news is that the lines into the trans cooler and the rubber hoses are good, the bad news is that I have a new problem to fix.

These fittings are not supposed to leak, so I think I may have damaged the o-ring when I removed the old line. I ordered a new one we'll see what happens. Anyone else have this problem?

Anyone know the torque spec for the fitting?

Sent from my SM-G935V using WAYALIFE mobile app
 
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