Transmission Cooling Line Repair?

[EddieC]

2008 Tahoe: My upper transmission cooling tubing is leaking at the crimped upper connection of the short (flexible?) section with crimped connectors in the rear of the engine compartment. I question flexible because it is the short intermediate section inside what appears like a black wiring harness protector. I don't know but suspect there may be a rubber hose inside.

I previously added a hose clamp that I thought was going to be the ticket but is weeping a bit.

It appears that it would be tough to replace the entire tube from radiator to transmission because of the tough to reach fitting on the top of the transmission so the question is has anyone successfully fitted in a replacement for the flexible section and, if so, what recommendations can be shared?

Is there much pressure in that line that would require special consideration?

 

[blackelky]

Both of the lines from rockauto ac delco brand are 80$. Not a terrible job to do either

 

[EddieC]

Both of the lines from rockauto ac delco brand are 80$. Not a terrible job to do either

I'm not so concerned about the price as much as not seeing how to reach the fittings atop the tranny

 

[gooffeyguy]

When I installed a remote external trans filter I ended up cutting the hard tubes on each side of the rubber hose that's located between the front of the motor and radiator and used these TruCool 3/8 compression to 3/8 barb fittings and ran transmission hose. Also used spring style hose clamps because worm style hose clamps would cause seeping during the winter and need tightening.

 

[EddieC]

When I installed a remote external trans filter I ended up cutting the hard tubes on each side of the rubber hose that's located between the front of the motor and radiator and used these TruCool 3/8 compression to 3/8 barb fittings and ran transmission hose. Also used spring style hose clamps because worm style hose clamps would cause seeping during the winter and need tightening.

View attachment 421206

I like that! I imagine that the lines have to be pretty new/clean for the compression fittings though, right?
Mine are original from '08.

 

[gooffeyguy]

I used a tubing cutter, like used to cut copper and aluminum pipe, to cut the lines and debur the ends.

The trans lines aren't under a lot of pressure, like 30-50psi.

Derale makes these fittings also

Universal 3/8" Transmission Cooler Line to 3/8" Hose Barb Compression Fitting

Universal 3/8" Transmission Cooler Line to 3/8" Hose Barb Compression Fitting Cooling Line Radiator Adapter Fittings 3/8" Compression Fitting Kit 13032

derale.com

 

[donjetman]

I replace my cooler lines (rpo code KNP) in 2018
25999420 (2 lines in one), and 15779543.
I did it while doing the oil pump pickup tube o-ring job, etc.

 

[EddieC]

I used a tubing cutter, like used to cut copper and aluminum pipe, to cut the lines and debur the ends.

The trans lines aren't under a lot of pressure, like 30-50psi.

Derale makes these fittings also

Universal 3/8" Transmission Cooler Line to 3/8" Hose Barb Compression Fitting

Universal 3/8" Transmission Cooler Line to 3/8" Hose Barb Compression Fitting Cooling Line Radiator Adapter Fittings 3/8" Compression Fitting Kit 13032

derale.com

Is using fuel line ok?
Derale oil line price is not reasonable.

 

[gooffeyguy]

Is using fuel line ok?
Derale oil line price is not reasonable.

Don't know, I've never used fuel line for trans fluid, but I'd like to think that there is some reason they make trans line. Maybe more heat resistant. Trans fluid gets pretty hot while fuel doesn't.

 

[blackelky]

I'm not so concerned about the price as much as not seeing how to reach the fittings atop the tranny

is that a 4l60e? The 6l80 are on the side of the trans

 

[EddieC]

is that a 4l60e? The 6l80 are on the side of the trans

4L60-E
(M30)

 

[Foggy]

NO, you cannot use fuel line for OIL/Trans Fluid

 

[iamdub]

I'm not so concerned about the price as much as not seeing how to reach the fittings atop the tranny

@OR VietVet just did a very similar repair and posted pics that should be helpful. Check it out here: https://www.tahoeyukonforum.com/thr...ish-i-didnt-turn-wrenches.142050/post-1853787

I'd recommend getting some flare nut wrenches. Or, if you have no need to add some to your tool collection, buy box end wrench(es) in the size(s) you need and use a grinder or cutoff disc or even a hack saw to notch the end to fit the line (~3/8"). For specialty tools like this, I hit up the miscellaneous loose tool bin at the pawn shop. You can grab an old, but good wrench (Proto/Challenger, old school Craftsman, etc.) that shouldn't break as the Harbor Freight ones are more likely to do.

 

[OR VietVet]

@OR VietVet just did a very similar repair and posted pics that should be helpful. Check it out here: https://www.tahoeyukonforum.com/thr...ish-i-didnt-turn-wrenches.142050/post-1853787

I'd recommend getting some flare nut wrenches. Or, if you have no need to add some to your tool collection, buy box end wrench(es) in the size(s) you need and use a grinder or cutoff disc or even a hack saw to notch the end to fit the line (~3/8"). For specialty tools like this, I hit up the miscellaneous loose tool bin at the pawn shop. You can grab an old, but good wrench (Proto/Challenger, old school Craftsman, etc.) that shouldn't break as the Harbor Freight ones are more likely to do.

Broke everything loose with 1/2" line wrench. Then used a short open end to remove. Started all fittings by hand and finished running them down with open end and tightened down with the line wrench. Went well. Radiator area was plenty of room. At the transmission was tight with lots of wrench flipping.

 

[j91z28d1]

I've not done tranny lines but I have messed with oil lines, same style hose and crimps that seep and leak.

don't waste your time trying to repair these things.. either replace the whole thing front to back or change to a PTFE style hose and AN fittings. (very expensive) nothing in between is really worth the hassle and if they fail, it's expensive and a mess.

 

[OR VietVet]

NO, you cannot use fuel line for OIL/Trans Fluid

Absolutely agree. Fuel line is for fuel. Oil line is for oil. Transmission fluid line is for transmission fluid. Pretty simple concept.

 

[EddieC]

@OR VietVet just did a very similar repair and posted pics that should be helpful. Check it out here: https://www.tahoeyukonforum.com/thr...ish-i-didnt-turn-wrenches.142050/post-1853787

I'd recommend getting some flare nut wrenches. Or, if you have no need to add some to your tool collection, buy box end wrench(es) in the size(s) you need and use a grinder or cutoff disc or even a hack saw to notch the end to fit the line (~3/8"). For specialty tools like this, I hit up the miscellaneous loose tool bin at the pawn shop. You can grab an old, but good wrench (Proto/Challenger, old school Craftsman, etc.) that shouldn't break as the Harbor Freight ones are more likely to do.

I wish my tube routes and connection access on the tranny were so simple as yours.

 

[OR VietVet]

I wish my tube routes and connection access on the tranny were so simple as yours.

At Inline Tube, some of the lines come in two pieces for ease of install. You can call them and see what they can make for you.

 

[EddieC]

At Inline Tube, some of the lines come in two pieces for ease of install. You can call them and see what they can make for you.

I need an 8 year old's hands to get to the transmission connections behind the exhaust. Right there the pipe expands out looking like a boa that swallowed something big.
I'm afraid that's one of those jobs that someone else gets to carry the headache but it's worth trying a repair first.

 

[iamdub]

I wish my tube routes and connection access on the tranny were so simple as yours.

His trans is a 700R4, which is essentially the same as the 4L60E, at least, in this case. It sure looks like mine. Your '08 should be like mine. Or is yours a 4WD and that makes it more complicated?