Transmission: Radiator by-pass? | Ford Explorer Forums - Serious Explorations

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Transmission: Radiator by-pass?

SwaintaN

Explorer Addict
Joined
March 15, 2008
Messages
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City, State
Carey, Ohio (Georgia Grown)
Year, Model & Trim Level
93 XLT
So wonder if we can by pass the transmission lines connected to the radiator and just run them into the line cooler (in front of tranny) and back to transmission? i have two line coolers, stock and aux i installed a while back. Would the holes in the tranny have to be plugged or can stay unplugged? is it even possible to do this with out complications to the tranny?
 



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More info... In Ohio.. gets driven in summer for play time (mudding, camper pulling) in winter, only drive for the snow to deep and not plowed situations... here is pic before a/c stuff removed... so this is the before pics.. but the aux line cooler is now attached to the rad..

0015.jpg
 






I did this with the Mounty, and it was done by the previous owner of my 93.

The transmission "cooler" in the radiator is actually a fluid "warmer", by the way. You might find you need to reconnect it in winter, as cold trans fluid is hard on the transmission also.

Remove the lines, go straight to the coolers and you will see lower temps in summer.
 






Just to get it into this thread too (not just your a/c thread).. here is what we use.

Here is the biggest one I could find and I'm using it for the Van. This is the only cooler used on the van with a c6. I don't think I've seen pan temp > 170 yet, even when going uphill with total vehicle weight (with trailer etc)of 14,000 lbs.

3959944815_373e989017_z.jpg

cooler-installed 002 by maniak_az, on Flickr

Info on that cooler is...
Tru-Cool # LPD4739-1 cooler plus a # 708-4739 Remote external thermal bypass
40,000 GVW rating, 45,000 BTU rating
8 1/2 x 22 3/4 x 1 1/4 inch 3/8 fittings.


On the explorer, I'm using 2 aux coolers, in series and a 10" fan from a collora/geo prism and I have the heat exchanger in the radiator bypassed (I just put plugs in the radiator heat exchanger)

They are both stacked plate (more efficient) and I'm not sure but I think one is 20,000 gvwr and the other is 25,000 gvwr.

3454387446_562f609c46_z.jpg

Transmission-cooler-misc 005 by maniak_az, on Flickr

Oh yea, while I was putting these in I did also install an external trans filter too.

~Mark

Edit: I just double checked the X (was going to take a pic of the plugs). Apparently, sometime over the last year or so I have put the fluid back into the radiator. It is running from trans to external filter to radiator exhanger to a cooler, to another cooler back to the trans. I forgot that I did that..
 






The transmission "cooler" in the radiator is actually a fluid "warmer", by the way.

Jon,

That's a misnomer. Heat transfer is much faster between 2 fluids than between fluid and air.

The engine coolant runs cooler than the fluid coming out of the transmission. By running the fluid through the radiator, you strip off a significant amount of heat quickly. The cooler fluid is now easier to cool with air.

Your transmission will run cooler if you cool the fluid in the radiator then an external cooler as opposed to only 1 or 2 external coolers.

(Source: Performance Automotive and Transmission Center)
 






I noticed only a small difference in transmission pan temperature running via the heat exchanger (radiator) first or right to the trans coolers. Pulling the trans fluid out of the radiator would make there less heat to pull via the radiator though.

On 1st gen explorers, the fluid is always going out to the coolers/radiator/exchanger, unlike some later fords which keep the fluid from running into the coolers until they have sufficient heat. That means when the transmission temp is cold (like in below freezing weather) the radiator heat exchanger is actually warming the fluid up.

So, in short, if the trans fluid is warmer than the engine coolant than the trans fluid will be cooled. If its colder than the coolant it will be warmed up. That 2nd scenario is what I think Jon was talking about, not that it always warms it up.

~Mark
 






Jon,

That's a misnomer. Heat transfer is much faster between 2 fluids than between fluid and air.

The engine coolant runs cooler than the fluid coming out of the transmission. By running the fluid through the radiator, you strip off a significant amount of heat quickly. The cooler fluid is now easier to cool with air.

Your transmission will run cooler if you cool the fluid in the radiator then an external cooler as opposed to only 1 or 2 external coolers.

(Source: Performance Automotive and Transmission Center)


I noticed a huge temp difference when I bypassed my radiator in the Mounty.

Even with 2 external coolers, trans temps would rise to coolant temps at idle and slow speeds. Bypassing my radiator was the ticket. Yes I had switched fans on the coolers.

Remember, the fluid to fluid exchange in the radiator is 195 degrees---way higher than the trans temp should be. Running cooled 140 degree trans fluid into a 195 degree raditor makes no sense,

You yourself witnessed the result in Colorado, the prior year I was having to stop during each climb to cool down. I had no issues whatsoever with trans temps the 2nd time around, after bypassing the radiator.
 






Ok so im gonna still use the rad i guess for now.. i got the top line all fixed with some hose about 8" long, sealant and 4 clamps.. now the bottom is worse.. haha.. i cant seem to fix it... so here is my idea

Old Stock on on the left... radiator at the bottom... next (black) it the nut that goes in to the radiator, (brown) is the nut on the end of the stock line, (green) is stock metal line...

now pic on right.. is the custom one im thinking of... Still rad at bottom pic, (black) is the stock nut, then (blue) take a elbow that threads into the stock (black) big nut (of course with tape). then (grey) part is a barbed fitting threaded into the elbow with sealant as well.. the rubber hose (with clamp) onto the barbed fitting... hose runs to line cooler... this instead of the metal line... would this work?

Custom.jpg


busted part
trannylinefitting.jpg
 






radiator temperature

The engine coolant temperature is maintained by the thermostat which is typically 195 degrees. However, the temperature of the radiator is normally much less than that. Since I have the 5R55E my external cooling path does not open until the temperature in the torque converter reaches 150 degrees. I have a remote ATF filter and two of the stock ATF coolers. I do not run the ATF thru the radiator and typically the ATF temp stays less than 170 degrees but I don't tow anything of significant weight. I have two remote engine oil filters and an external engine oil cooler. I run my engine oil thru the radiator but sometimes in the winter my engine oil temperature is less than optimum. When I switch to a V8 I plan to add thermostatic control of both the ATF and the engine oil to keep both at optimum temperature.
 






so that busted line that noone around here wants to sell the parts to... well i just made a replacement... love lowes.. haha, but the hose is from advance..

this way i can still use it through the radiator and not by pass it.

parts
fixedlineparts.jpg


together, have clamps and barbed fitting for hose to hose connections
fixedline.jpg
 






This works without any leaks? I'm looking to do this for a leaking line. Nobody has the parts (just like you said) for the fitting. I'd like to build a replacement as well. Where should I be looking in the hardware store for this? And what size are the threads? Also, is it necessary for it to be an elbow joint?
 






No leaks at all, i did the Elbow to give it a cleaner look, plus to direct the hose. I got all my stuff from Lowes. On size.. dont remember if it is the trann line from radiator, just take the part in with you and match it up. wish i would know where the receipts were then i would just tell you what i used.


edit: found it. Read my project hex... this post to be exact that give you exactly what i used even part numbers

edit 2:
so you know them hard to find lines and you always gotta rush around trying to find at a junk yard just to find out junk yards nor ebay has that line.... i fixed that... the bottom tranny line that goes into radiator busted big time.. and when reinstall, top line busted.. i was lucky enough to find a line from a member on here and fix the line with it and some hose.. bottom... well i rebuilt it.. this goes right into the long nut that is on the radiator..

parts list from lowes:
pipe tape
A-182 3/8 Flar x 1/4" MIP, half union
a-739 1/4" mip x 1/4" fip, street elbow
a-732 1/4 fip, pipe coupling
a-201B 5/16" barb x 1/4" mip, hose barb adapter
Enough hose to reach desitnation
A-201A 5/16" Barb Splicer
2 Clamps

fixedlineparts.jpg

fixedline.jpg
 






Thanks man! I'm going to head to the store and pick these up. Here's hoping all goes well!
 












Worked like a charm! Thanks dude!
 












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