Tranny Lines

[hogfarm]

Bulding auto trans cooling lines.dothey need to have a rubber flex joint?

[Dave0]

Yes

[DransportGarage]

Originally Posted by hogfarm

Bulding auto trans cooling lines.dothey need to have a rubber flex joint?

In my opinion, no. They need a few bends so they can shrink and expand a little, preferably a couple near 90 degrees. That's the way they were made back in the day. Any rubber part of the line will be the weak link from a pressure standpoint and may deteriorate due to contact with the trans fluid.

[OrrieG]

Originally Posted by DransportGarage

Any rubber part of the line will be the weak link from a pressure standpoint and may deteriorate due to contact with the trans fluid.

Not if you use hydraulic equipment rated hose from a place that makes them for commercial equipment like back hoes, etc. Fuel rated hose is not good enough.

[HUSSEY]

Some OEMs have rubber flex lines and some don't. There's not much pressure in the trans cooler lines so I wouldn't be concerned at all with a rubber flex line. Just make sure you use a rubber line that is compatible with transmission fluid.

[DransportGarage]

Originally Posted by OrrieG

Not if you use hydraulic equipment rated hose from a place that makes them for commercial equipment like back hoes, etc. Fuel rated hose is not good enough.

Hi Orrie, it would be interesting to see if the steel was stronger, or the rated hose. I have a feeling the rated hose might win that one. They typically are good for 3000+ psi.

[_Ogre]

Originally Posted by hogfarm

Bulding auto trans cooling lines.dothey need to have a rubber flex joint?

not if you build them right. rarely does an oem cooler line have anything but steel
truk has all ss steel lines, i ran them down the oil pan flange straight out to the radiator
the oil pan flange is approx the center of the motor and has minimal flex

27,000 miles and that is the least of my worries

[72Mountaineer]

I did mine in all steel.

[mr48chev]

Nice job(s) there on both of those Ogre and 72Mountaineer. I'd agree that in the majority cases there is no need to put rubber lines in.

From experience the rubber line or where it connects to the steel line or the cooler is always where the leak is.

[72Mountaineer]

We've all used rubber lines for these types of things before. If you can put a bubble flare on the steel line, go for it. It might last 10 years before anything happens, maybe never. Tranny fluid can keep the rubber in better condition than the **** gasoline we all buy today.

[dsraven]

I just replaced some OEM rubber hoses on a gm diesel, the rubber was rated for 300 psi. it was the crimp that gave out, not the rubber.
a rubber flex is not a bad idea or at least leave some space between tie downs for the lines to flex if going all solid.

[1project2many]

It's very common to see rubber / steel combination lines today. I can't begin to count how many I've seen fail. Common practice today is to use an aluminum band crimped around the hose at the steel tube. The hose usually shrinks and starts to fail.

If you are going to use all steel tubing you need to allow for flex and motion in the driveline. Typical OEM practice is to route the line along the engine/trans combination then support it somewhere near the engine mount. From that point the line is often unsupported until it connects with the radiator / trans cooler. Bending is allowed across a fairly long amount of tubing. It is also possible to create expansion or flex loops such as found on brake tubing below the firewall.

I agree that the quality of hose makes a large difference in a steel/rubber combination. So does the clamp. Norma Torro clamps (aka European Hose Clamps) are an excellent choice for a high tension clamp on a rubber line.

[hogfarm]

I have decided to use rubber steel combo.Today I will make an aluminum blockI can bolt to the frame across from the Tranny and conect with hydraulic hose,then from aluminum use steel to cooler.I dont have a milling machine ,so it will just take me a little longer squaring the block on my Lathe I will get pictures,Thanks for all the help

[dsraven]

a good hydraulic hose place could put together a hose with fittings to match the trans cooler end and also a compression fitting to fit over your steel line. that is a common fix on newer style chevy trucks with the poorly crimped trans cooler hoses. hose shops simply supply a new hose with compression fittings on each end that fit onto the old steel or aluminum lines.

[_Ogre]

going to the frame maximizes the flex on the cooler lines
look at the routing down the oil pan flange for minimal flex
truk has no couplings or fittings other than each end of the lines

[DransportGarage]

Originally Posted by _Ogre

going to the frame maximizes the flex on the cooler lines
look at the routing down the oil pan flange for minimal flex
truk has no couplings or fittings other than each end of the lines

X2. I'll just pull my hair out instead of commenting further.

[donandal]

Some valid points here from several gentlemen.

I had very little room under/near the oil pan area on my 5.3 swap into my 53 pickup so I went over to the frame. Because I expected this would involve more flexing, I made this section with braided stainless hose with a Teflon inner lining that is designed for transmission fluid. From there it was made with steel hard line and fittings.

A bit more expensive, but I didn't want to do it over....ever.