Auxiliary trans cooler lines

[bab029]

I have an aux cooler on my truck (in front of condenser) and the rubber lines are starting to swell and show their age. First, what kind of pressure is running through these lines? I assume kind of low. Second, what type of hose to I need to seek out to replace them? The cooler splices into the hard lines from the trans using barbs and clamps.

Thanks!

 

[icanfixall]

I think those lines are 3/8 material. Just fuel rated hose is all you need. The pressures are about 60 lbs. Might go as high as 100 lbs but not for long. The temps will range from around 160 to 210.. Much higher and the trans lives a short life. I read somewhere the temps reaching 240 and above will result in a trans life of around 12 minutes.. Kinda shocking isn't it... Can't recal where I read this but the graph showed how long a trans lives at differant temps.

 

[bab029]

Thanks, I wasn't sure if trans fluid required some special kind of rubber or not. I'll get right on it before I develop a massive fatal leak.

 

[kc0stp]

Personally Id just get tranny hoses vs fuel line... (yes there is a hose just for tranny lines your average parts store should have it)

 

[LCAM-01XA]

I think those lines are 3/8 material. Just fuel rated hose is all you need. The pressures are about 60 lbs. Might go as high as 100 lbs but not for long. The temps will range from around 160 to 210.

Negative on all counts but the pressures, those I am not sure of.

1) lines are 5/16" unless changed by previous owner. That said I flared mine good at the end, and I'm using 3/8" hoses - even little helps is better than nothing at all. Ideally you want 3/8" all the way, and IIRC the BTS and other high-end transmissions are set up for those. Just not the factory ones.

2) "just fuel rated hose" aka SAE 30R7 hose is a 50 psi hose that is incompatible w/ transmission fluids in the long run. Fuel-injection SAE 30R9 hose (100psi) may be better as it's designed for low permeation by whatever runs thru it, however it's not anywhere near as cheap. The correct hose to use is SAE J1532 transmission oil cooler (TOC) hose, this is often 140-150 psi hose of material designed to survive against transmission fluid. Your local parts store will have it, just read on the hose what it says.

3) fluid temperature on the converter discharge line can get a whole lot higher than 210 degrees. Especially when pulling a grade in 2nd at wide open throttle. Nothing to be alarmed about, if the coolers are doing their job the pan fluid temp will stay in the manageable levels, and transmission will live a long and happy life. However the rubber piece between the "hot" steel line and the in-radiator heat exchanger will see all those high temps the converter is producing. And fuel hose is not a very high-temp hose.

Useful links:
http://www.goodyearep.com/productsdetail.aspx?id=10526
http://www.goodyearep.com/ProductsDetail.aspx?id=5144
http://www.goodyearep.com/productsDetail.aspx?id=6078

 

[Wicked97]

They are 5/16. Skip the fuel or tranny cooler Lind and use the orange Goodyear multipurpose hose. It lasts a lot longer

 

[RLDSL]

Sorry Gary, but fuel hose will fall apart with long term exposure to tranny fluid. Most parts stores will carry a special hose rated for tranny coolers( it looks shockingly like power steering return line but generally a tad stouter. PS line will work in a jam.


If you dont want to fool with it again, get some aeroquip hose on there. You can use the stuff with worm gear clamps, although it puts up a fight. If the barb fittings are threaded in you can replace those with AN fittings and you can get adapters for teh truck connections and once you do that you wont have to worry about that hose for about another 700,000 miles

 

[icanfixall]

Well I have been corrected and I thank you guys for that.. I have always run the fuel rated hose but not any longer will I do that... As for the size... I see the truck is the 92 year so thats about when they changed to the larger 3/8 hose. Could it be still a 5/16.. Sure could but checking it is best... I know about 12 years ago I was at work cutting my return line to the trans to install a fitting when I found out I had the 5/16 line... Big surprise under thet truck that day. Really had to search for a 5/16 coupler to fix my mistake... Never did install that fitting... Replace the trans about a year later with a Jaspers rebuilt trans that came with the upgraded stainless steel 3/8 lines... Thats stil the same braided lines I'm running today... Funny how I got away with fuel hose in this area for so long on many of my trucks.. But wont any longer.. Thanks for the great information...

 

[trackspeeder]

89-97 E4OD use 5/16" cooler lines. 98 E4OD is the only year to use 3/8" lines.

 

[LCAM-01XA]

89-97 E4OD use 5/16" cooler lines. 98 E4OD is the only year to use 3/8" lines.

Any transmission case mods needed for this? OR is it just in the fittings and lines? How about using 4R100 fittings and lines, is that doable fairly easy?

 

[icanfixall]

Yes, the rear port in the trans needs to be drilled out and threaded for the 3/8 inch pipe threads but... Now this is the important part... You need to tap 3/8 STRAIGHT PIPE THREADS IN THE TRANS... Taper threads wont work because the check valve fitting that goes back thee has an o ring seal on it. Nope.. You can't run without that check valve either.. The fluid will drain out of the converter every time you shut down the engine.. Then it takes time to refill the converter when you start up again.. The 3/8 straight thread pipe tap is a tuff one to find.. This straight thread pipe threads is a common use in the electrical conduit business. BTW never mix tapered pipe threads with straight cut pipe threads. It will never hold water and its tuffer than hell to figure out whats wrong... Both taps look alike but a close look at them will tell you they are differant.. When I got my BTS trans I had the small 5/16 fitting in it even though I told them I was running all 3/9 fittings and braided staniless steel hose... I used a 1/2 inch drill motor and drilled out the trans. Then I used a tap to cut the required threads. All this was done with the trans completely together. I filled the hole with cotton to drill it out. Then washed out the chips. Hooked the cotton and pulled it out. Then filled the hole in the trans with heavy axle grease. Coated the tap with light grease. Started tap work but stopped about 1/4 of the depth needed. Cleaned out chips. Coated the tap again and finished the job. The tap kept all the chips and nothing went past the grease pack. It acted like a finger in the dam plug. Nobody was hurt doing this... It was do that or ship the trans back to Arkansas for modifications at thier expense but actually it was on my time.. I wanted my truck back on the road..

 

[LCAM-01XA]

Sounds like fun. Was your transmission also installed in the truck at the time? What about the front (converter discharge) fitting, same work needed or is it a direct bolt-on affair?

 

[trackspeeder]

For those who want to upgrade to 3/8" lines the easy way. Stop by your favorite Ford dealer and get the 98 E4OD bypass or 99 and up 4R100 bypass (same part). If you can get a used part it can be rebuilt using a Sonnax rebuild kit.
This is a bolt on part, no drilling, or cussing needed. Well maybe cussing. most Ford's need that.

The reason for a bypass is to keep the tranny from totally coming apart if there is a cooler restriction.

 

[LCAM-01XA]

OK, so the opening in the return port is large enough to support the flow thru a 3/8" line, just the fitting that goes in there and drops line size to 5/16" is goofy and don't exist in the same thread but for larger line? Hence why Ford is able to make use of 3/8" lines with a setup that threads right in place w/o any drilling needed?

Excellent info, and I do like the emergency bypass idea. Do you know what pressure its valve opens at to allow cooler bypass? Reason for asking is I got a 6-micron filter on the hot line before the radiator, it is also where my temp sensor is installed - I figured hot fluid will flow thru filter easier than cool fluid, but still I don't wanna end up with the filter backpressure forcing the bypass valve open all the time. And if you got a part # for that bypass kit that would be very awesome!

 

[trackspeeder]

I'm not sure what the pressure rating is on the bypass. I don't see a problem with your filter, unless it's plugged. A plugged filter will trip the bypass. Just like a restricted cooler.