1994 K1500 Trans Cooler Lines Leaking

[Striker1423]

On my truck I had a massive cooler line leak, so I ordered a stainless steel kit from Lines to Go and set about following their replacement video here:

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I tightened the lines, started the truck and all was good at the trans, adapter end, and main lines except I had a leak at the top and bottom flares for the in/out adapters on the transmission itself. I grabbed my short wrench and cranked them both tighter and the leak appeared to stop. Drove it around a while and got out to look. A drip was on the bottom of the top trans line (obviously flowed down the line to the bend). Looking at the fitting it still is leaking between the line and threads, just slowly. I loosened and re-tightened the fitting again with my stubby wrench to the awkward point my hand made a lovely crunching noise and now hurts, but the leak persists. Is this typically a flare issue? I suppose it's possible a piece of dirt got up there as getting the lines into position was a cluster and a half laying on the ground... Easy my ass. The flares looked just fine to me, so I don't know what else to think.

Should I pull the line back out of the adapter and see if I can't get it to reseat?

 

[Komet]

Bad flares will leak, that's always a possibility. Dirty / rusty threads will leak too. I'd say the likelihood of a manufactured flare being poorly shaped is relatively low, and it's usually been my experience that leaking flares are not tight enough yet.

Here's the deal; a stubby wrench isn't going to cut it when it comes to the torque needed to get that flare sealed. In fact, any open-ended wrench is not capable of transmitting the torque needed because it'll round the flare nut first, and then you're redoing the flare. What you need are flare nut wrenches to achieve the grip needed to crush those closed. Snap-on flare nut wrenches are the best and this is the one time where I actually recommend going all the way to the top to buy a tool because you need that wrench to not flex in a very serious way, and Snap-on forgings are very seriously good.

 

[Striker1423]

I agree good flare wrenches are a must, but I don't think they'll fit up in the area... Hmm. Do you think a crows foot will work?

 

[Komet]

It could. I forgot how tight that area is, I did mine with the trans crossmember removed and the trans hanging down I think.

 

[Erik the Awful]

You can get crow foot flares.

3/8 in. Metric Crowfoot Flare Nut Wrench Set, 7-Piece

Amazing deals on this 7Pc 3/8In Metric Crowfoot Flare Nut Wrench at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

I'm all for buying quality when it makes sense, but the Strap-On set is twenty times the price!

Snap-on Store

shop.snapon.com

 

[scott2093]

I'm all for buying quality when it makes sense

Can't say I've found a need like this yet but still interesting....

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[Striker1423]

Well... to add to the trouble I now have a 2-3 shift flare when hot. Never did this before. Okay I have to backup some.

My lines leaked like a sieve. Bought the truck about a month ago. Had 107,800 on the clock and of course it leaks everywhere. Rear main (engine oil), between the T-case and Trans. T-case itself. List goes on. She was topped up with fluids when myself and a buddy drove it home. No issues in 250 miles.

The truck drove fine, but it was around 1.5 quarts low when I checked it after replacing the cooler lines. I topped it up with some maxlife I bought and called it good and the truck shifted less harshly, felt more smooth, sounded good, etc. Obviously the lines still leak some (small drips) hence this topic, but not enough to go down a quart in the whole 4 times I've driven it less than 30 miles. Headed home and the truck started 2-3 flaring on me within a mile of the house at mid-throttle, right before the gas pedal stiffens up (at the point the motor would rev-up and a downshift would occur). Felt the top cooler line and it was very hot. Bottom felt warm. Checked the fluid and from what I can tell, it doesn't smell burnt or anything. Just smells like nasty ass trans fluid and is still red. Seemed to be where I had it (just a CH above the top line on the dispstick).

What I wonder is, am I mis-checking the fluid level? I check it in park in my somewhat level driveway when its hot. The dipstick reads fresh fluid, even though its really hard to see, its in the hash lines and seems right where it was when I filled it last...

 

[Komet]

I'm all for buying quality when it makes sense, but the Strap-On set is twenty times the price!

Ironically, it was that exact HF kit that spread on me and ruined my fasteners that drove me to get Snap-on used on ebay. In a low buck scenario, I think I'd choose a used Snap-on single piece than the HF kit simply because I know it would do the job.

Well... to add to the trouble I now have a 2-3 shift flare when hot. Never did this before. Okay I have to backup some.

My lines leaked like a sieve. Bought the truck about a month ago. Had 107,800 on the clock and of course it leaks everywhere. Rear main (engine oil), between the T-case and Trans. T-case itself. List goes on. She was topped up with fluids when myself and a buddy drove it home. No issues in 250 miles.

The truck drove fine, but it was around 1.5 quarts low when I checked it after replacing the cooler lines. I topped it up with some maxlife I bought and called it good and the truck shifted less harshly, felt more smooth, sounded good, etc. Obviously the lines still leak some (small drips) hence this topic, but not enough to go down a quart in the whole 4 times I've driven it less than 30 miles. Headed home and the truck started 2-3 flaring on me within a mile of the house at mid-throttle, right before the gas pedal stiffens up (at the point the motor would rev-up and a downshift would occur). Felt the top cooler line and it was very hot. Bottom felt warm. Checked the fluid and from what I can tell, it doesn't smell burnt or anything. Just smells like nasty ass trans fluid and is still red. Seemed to be where I had it (just a CH above the top line on the dispstick).

What I wonder is, am I mis-checking the fluid level? I check it in park in my somewhat level driveway when its hot. The dipstick reads fresh fluid, even though its really hard to see, its in the hash lines and seems right where it was when I filled it last...

I don't think you're mis-checking the fluid level. It's my understanding that the trans can't actually be damaged by being overfilled; it'll simply puke the too much out the breather if you manage it. If you got fluid on the stick between the lines, that's good. I'm suspicious that you bought the truck this way and the previous owner smoked the trans by letting the fluid level get too low. You could try dropping the trans pan and see what sort of clutch material is waiting for you in there. If it's not too agressive, fill it back up with some more fresh fluid and some stop-slip and hope for the best.

 

[scott2093]

could throw a Transgo kit and servo while in there??

I probably wouldn't have found a busted spring had I not...

 

[NickTransmissions]

Well... to add to the trouble I now have a 2-3 shift flare when hot. Never did this before. Okay I have to backup some.

My lines leaked like a sieve. Bought the truck about a month ago. Had 107,800 on the clock and of course it leaks everywhere. Rear main (engine oil), between the T-case and Trans. T-case itself. List goes on. She was topped up with fluids when myself and a buddy drove it home. No issues in 250 miles.

The truck drove fine, but it was around 1.5 quarts low when I checked it after replacing the cooler lines. I topped it up with some maxlife I bought and called it good and the truck shifted less harshly, felt more smooth, sounded good, etc. Obviously the lines still leak some (small drips) hence this topic, but not enough to go down a quart in the whole 4 times I've driven it less than 30 miles. Headed home and the truck started 2-3 flaring on me within a mile of the house at mid-throttle, right before the gas pedal stiffens up (at the point the motor would rev-up and a downshift would occur). Felt the top cooler line and it was very hot. Bottom felt warm. Checked the fluid and from what I can tell, it doesn't smell burnt or anything. Just smells like nasty ass trans fluid and is still red. Seemed to be where I had it (just a CH above the top line on the dispstick).

What I wonder is, am I mis-checking the fluid level? I check it in park in my somewhat level driveway when its hot. The dipstick reads fresh fluid, even though its really hard to see, its in the hash lines and seems right where it was when I filled it last...

Your fluid fill and check procedures appear to be correct...2-3 flaring is usually worn 3-4 clutch pack in transmissions with a lot of miles (100k and up)....especially if it starts when hot. It may be time to yank it out and overhaul it. The pack may or may not have been damaged while fluid was low as all auto transmissions are super-sensitive to fluid levels...

could throw a Transgo kit and servo while in there??

I probably wouldn't have found a busted spring had I not...

Definitely during overhaul but 2-3 flaring at this point usually means rebuild time.

It's my understanding that the trans can't actually be damaged by being overfilled; it'll simply puke the too much out the breather if you manage it.

In most cases but if the volume overwhelms the vent system, fluid will begin to foam and pump will cavitate, eating itself - this applies to more extreme cases of overfill but 1-2 quarts should be manageable for the vent system.