H3 Transmisson Line Leaking

[jphh20]

I tried doing a search and didn't see that anyone has attempted a transmission line repair. I am starting to develop a leak on my transmission line between the trans cooler and the hard transmission lines. The leak appears to be coming from the flexible rubber hose and the hard line interface. I was first thinking it might be easy to replace the entire line however the trans lines do not appear to have a break in it until the back of the transmission. My question is: has anyone cut and flared there current lines? I haven't done a flare before but it appears straight forward for an easy replacement in the future. Has anyone attempted this and have any advice?

 

[MaxPF]

Are they aluminum? If so, I would TIG weld a male -6 AN fitting onto it. Whether or not you can successfully flare it depends on the specific alloy. Another option is AN compression fittings.

 

[poncho1965]

I tried doing a search and didn't see that anyone has attempted a transmission line repair. I am starting to develop a leak on my transmission line between the trans cooler and the hard transmission lines. The leak appears to be coming from the flexible rubber hose and the hard line interface. I was first thinking it might be easy to replace the entire line however the trans lines do not appear to have a break in it until the back of the transmission. My question is: has anyone cut and flared there current lines? I haven't done a flare before but it appears straight forward for an easy replacement in the future. Has anyone attempted this and have any advice?

Mine is leaking the same spot. I guess that section is there as an expansion joint of sorts? Mine is just seeping at this point......

 

[MaxPF]

Mine is leaking the same spot. I guess that section is there as an expansion joint of sorts? Mine is just seeping at this point......

No, just excessive crimps on the manufacturers part. Or it may be the hose used. I know DMax trucks have the same issues with the Ally trans lines. You also see it on oil cooler lines in some vehicles.

 

[Mr_Rich]

I've modified the trans lines on my K1500 with a double flare tool. It all depends on how good the tool is and how much skill you have with the flaring tool. If the trans lines are the kind with a captured O-ring then it may be as simple as replacing the O-ring to get a good seal again.

 

[poncho1965]

No, just excessive crimps on the manufacturers part. Or it may be the hose used. I know DMax trucks have the same issues with the Ally trans lines. You also see it on oil cooler lines in some vehicles.

But why the rubber hose crimped between the aluminum hard line? Purpose?


Mike

 

[MaxPF]

But why the rubber hose crimped between the aluminum hard line? Purpose?


Mike

Motion isolation. The engine/trans assembly is mounted on compliant motor mounts, and the frame itself flexes and twists. Without rubber the hard lines would have to absorb the motion difference between the trans and the radiator. Older trucks like mine did this, and it seemed to work OK with the old copper/brass radiators. My guess is the same setup with the plastic tanks would break the cooler fittings eventually.

I should add that the good compression fittings designed for hydraulics (and the aluminum versions designed for adapting AN lines) are the easiest way to replace the rubber. Unfortunately, I bet the tubing used is metric, and AFAIK the compression fittings are only available for inch-size tube. I could be wrong though... wouldn't be the first time I used the aluminum versions on my fuel lines, and a steel hydraulic version on my PS pump discharge. Both have been absolutely trouble free.

 

[poncho1965]

Ok cool, gives the line a place to flex as I suspected. But how do we fix it as the owner? Not eliminate the rubber hose. But fix it as a shade tree mechanic. Without being able to weld aluminum fittings...


Mike

 

[jphh20]

Thanks for all the replies, I am going to see if I can cut the line back and adapt a universal flexible line in its place. This would make it replaceable at the weak spot and more coat effective. I think the online prices for new lines were north of $125 beans for Hummer replacement lines.

 

[MaxPF]

Ok cool, gives the line a place to flex as I suspected. But how do we fix it as the owner? Not eliminate the rubber hose. But fix it as a shade tree mechanic. Without being able to weld aluminum fittings...


Mike

Measure the OD of the lines. If it is inch-size line, use AN compression fittings.