Leaking Transmission Cooler Lines

2zl · September 9, 2011

I have a 2007 Silverado NBS with a 4.8 and the 4 Speed auto.

Was wondering if anyone has repaired these on there own or changed them out with aftermarket or GM.

Is it a hard Job to do? Anything I need to Know?

Mine are weeping a little oil. and the dealer wants 450 to replace.

gm4yrs · September 10, 2011

I have replaced both lines when I added an external trans cooler. The connections are quick release with a horseshoe clip holding it in place. The space is tight, near side of transmission. If you are not sure to fix it, a shop did quote me $75 to install the lines. The clip must not be sprung, when clipping back on. Start the nook in a hole, and rotate around, to connect.

sillyazz · September 10, 2011

I have a 2007 Silverado NBS with a 4.8 and the 4 Speed auto.
Was wondering if anyone has repaired these on there own or changed them out with aftermarket or GM.

Is it a hard Job to do? Anything I need to Know?

Mine are weeping a little oil. and the dealer wants 450 to replace.

Where are they leaking at ?

2zl · September 10, 2011

I have a 2007 Silverado NBS with a 4.8 and the 4 Speed auto.
Was wondering if anyone has repaired these on there own or changed them out with aftermarket or GM.

Is it a hard Job to do? Anything I need to Know?

Mine are weeping a little oil. and the dealer wants 450 to replace.

Where are they leaking at ?

They are leaking at the crimped metal clamps, where the rubber meets the steel line.

txab · September 10, 2011

Easy to replace. You can also have yours repaired by a local hydraulic hose shop if you choose. you'll need to remove them though. Or you can run your own hydraulic rubber hose after cutting the crimps off and then hose clamping the new in place. Take your pick

2zl · September 11, 2011

Easy to replace. You can also have yours repaired by a local hydraulic hose shop if you choose. you'll need to remove them though. Or you can run your own hydraulic rubber hose after cutting the crimps off and then hose clamping the new in place. Take your pick

I was thinking of doing it right on the truck.

I have access to Hydraulic Fittings and Hydraulic hose.

What would be best to do? Flare the line to a bubble put the hose over and clamp? or Flare the line and put hydralic fittings(I guess AN) on it?

Will Hydraulic hose stand up to ATF? read somewhere that ATF has alot of detergents in it.

jblakeney · September 11, 2011

Every hydraulic hose I can think of that Eaton/Weatherhead produces will handle ATF.

Second, If I remember right those lines are aluminum. When aluminum is crimped it usually distorts. Which is perfectly fine if it is the first time it is crimped. However, the next time it is crimped it will leak. The OE line has been crimped and if you re-crimp it, its gonnnnna leak.

If the lines are leaking walk in the parts department purchase the lines, go home and replace them..... Or take it to an independent shop and have them changed.

Jbo

steakman · September 11, 2011

Every hydraulic hose I can think of that Eaton/Weatherhead produces will handle ATF.

Second, If I remember right those lines are aluminum. When aluminum is crimped it usually distorts. Which is perfectly fine if it is the first time it is crimped. However, the next time it is crimped it will leak. The OE line has been crimped and if you re-crimp it, its gonnnnna leak.

If the lines are leaking walk in the parts department purchase the lines, go home and replace them..... Or take it to an independent shop and have them changed.

Jbo

The lines are NOT aluminum, (at least on my truck they were'nt), they are in fact thin skinned steel lines aluminized for corrosion protection. This issue is chronic throughout GM's truck line up and has been ongoing since 1999 as far as i know.

Take a look at this write up I did about 2 years ago. I did it the expensive way, but there are much cheaper methods to permanently fix this issue. and why not spend the bucks...the dealer will only charge you a similar amount (after Warranty is up of course), for Lines that will in fact start to weep again. And its not the lines themselves, but the cheap aluminum crimps used where the non-reinforced rubber lines meet steel.

Trans|Lines fixed - Permanently

You May also want to look at this thread as well..in particular, post # 2

Re-Crimping Transmission Crimps/Hose

Hope that helps.?

Rgds

jblakeney · September 11, 2011

I ran down to my shop, I have a 3/4 ton in the air working on the rear brakes..... Sure enough, Steel that is Aluminium coated (engine oil & transmission fluid)..... Fully re-crimp-able.

I'd cut the crimp shell off and replace with a new crimp shell and hose. You can use Eaton/Weatherhead H101 series hose. It can be crimped in a portable Crimper like Atco 3710 or Mastercool. Without any issues.

I stand corrected on the line material. It passed the magnet test and is Steel. I have tried aluminum lines at re-crimping and they always leak they looked aluminum so, I assumed..... Now I have checked for myself and they aren't aluminum.

If your around my area bring them to me, I'll fix ya up.

Jbo

2zl · September 12, 2011

I ran down to my shop, I have a 3/4 ton in the air working on the rear brakes..... Sure enough, Steel that is Aluminium coated (engine oil & transmission fluid)..... Fully re-crimp-able.

I'd cut the crimp shell off and replace with a new crimp shell and hose. You can use Eaton/Weatherhead H101 series hose. It can be crimped in a portable Crimper like Atco 3710 or Mastercool. Without any issues.

I stand corrected on the line material. It passed the magnet test and is Steel. I have tried aluminum lines at re-crimping and they always leak they looked aluminum so, I assumed..... Now I have checked for myself and they aren't aluminum.

If your around my area bring them to me, I'll fix ya up.

Jbo

Would love to, I'm in Newmarket Ontario though.

tanked_darren · September 12, 2011

Easy to replace. You can also have yours repaired by a local hydraulic hose shop if you choose. you'll need to remove them though. Or you can run your own hydraulic rubber hose after cutting the crimps off and then hose clamping the new in place. Take your pick

I was thinking of doing it right on the truck.

I have access to Hydraulic Fittings and Hydraulic hose.

What would be best to do? Flare the line to a bubble put the hose over and clamp? or Flare the line and put hydralic fittings(I guess AN) on it?

Will Hydraulic hose stand up to ATF? read somewhere that ATF has alot of detergents in it.

lol yes it will

jblakeney · September 14, 2011

I ran down to my shop, I have a 3/4 ton in the air working on the rear brakes..... Sure enough, Steel that is Aluminium coated (engine oil & transmission fluid)..... Fully re-crimp-able.

I'd cut the crimp shell off and replace with a new crimp shell and hose. You can use Eaton/Weatherhead H101 series hose. It can be crimped in a portable Crimper like Atco 3710 or Mastercool. Without any issues.

I stand corrected on the line material. It passed the magnet test and is Steel. I have tried aluminum lines at re-crimping and they always leak they looked aluminum so, I assumed..... Now I have checked for myself and they aren't aluminum.

If your around my area bring them to me, I'll fix ya up.

Jbo

Would love to, I'm in Newmarket Ontario though.

Yah 1157.33 miles is quite the trip just to get some fittings smashed and some new hose...

Jbo