Adding aux. cooler without modifying TOC hard lines

[AP9]

Since my 5R55E seems to be running a bit hot (it's not uncommon for me to go over 200 at highway speeds and stop-and-go traffic on hot days) I'm thinking about adding an auxiliary transmission cooler.

I like to do as little modification to my vehicle as possible. I'd like to know if anyone else has done a setup something like this, which is what I'm considering:

Keep the TOC hard lines in place. Where they connect with the cooler that's integrated into the radiator, unscrew them and replace them with T-fittings (or Y-fittings). One end goes into the integrated radiator unit, and the other hand goes into TOC hoses which would lead to the aux. unit. So the two coolers would be running parallel to each other.

I'm trying to avoid leaks while doing as little modification as possible here, and am still not sure about the fitting sizes & types.

 

[PopRichie77]

The regular way is to run the rad output line to another cooler and then to the trans. That's the way the factory does it.
Doesn't your explorer have a stock aux cooler?

 

[AP9]

No stock aux. cooler, just the one integrated into the radiator. Wouldn't running the coolers in parallel rather than in series result in greater heat transfer?

 

[Maniak]

You normally run them in series so they spend more time in coolers.

I'd be afraid that If you ran them in parallel that you can't control the flow between the coolers so most of the fluid could go through a single cooler (less restrictive one). At that point your not getting the maximum cooling affect.

Some people run them through the Aux cooler first and then the heat exchanger in the radiator. That way it will still warm up your fluid during the cold season BUT, IIRC your transmission has a cooler bypass built into it. Until the fluid gets up to temp it doesn't let the fluid out to be cooled.

That means you really don't have to worry about over cooling your fluid so you could run it from the trans to the heat exhcnager to the aux cooler back to the trans. If the fluid does over cool the transmission will stop the fluid from running to the coolers.

~Mark

 

[AP9]

Running them in parallel should also mean less pressure drop, but I'd say that's less of a concern than overall cooling efficiency. Running in series does make sense if one cooler is significantly more restrictive though; I didn't really think about that before.

I'm wondering then if I should just completely replace the hard lines with more flexible hose, especially since the metal (high heat conductivity) hard lines are routed pretty close to one of the cats, thus heating the fluid back up again.

Does the late-2000 5R55E use 11/32" fittings?

 

[delexploder]

Just get the one off a v8 , I know my 97 sohc came with the aux cooler like the v8s either one wold fit

 

[PopRichie77]

My 99 came with the aux cooler and under normal conditions it rarely heat up. I do a lot of towing and I added another stock cooler, this works well but when towing up a mountain with the torque converter unlocked it still reaches 200 degrees but with out the trailer it doesn't go that high.
Are you sure your torque converter is locking up, no flashing OD light?
How do you know the trans is heating up, do you have a trans fluid temperature gauge?

 

[AP9]

Just get the one off a v8 , I know my 97 sohc came with the aux cooler like the v8s either one wold fit

The holes & mounting hardware should line up nicely then I assume?

My 99 came with the aux cooler and under normal conditions it rarely heat up. I do a lot of towing and I added another stock cooler, this works well but when towing up a mountain with the torque converter unlocked it still reaches 200 degrees but with out the trailer it doesn't go that high.
Are you sure your torque converter is locking up, no flashing OD light?
How do you know the trans is heating up, do you have a trans fluid temperature gauge?

This vehicle has never towed a trailer. I got a ScanGauge II about a month ago and have been monitoring transmission temperature ever since. By the end of my 30-minute commute (which sometimes includes lots of stop-and-go traffic) I'm usually at 185-195. Got up to 209 once.

No flashing O/D light, transmission feels like it's working fine, but a few weeks ago CEL did come on once. Got code P0715, cleared it, and nothing since.

 

[PopRichie77]

Just something to add 200 degrees F is not to high, the boiling point of trans fluid is around 600 degrees F, old fluid will boil at a lower temp.

 

[delexploder]

Yea I would try to round up a factory setup, for what you need it would be the way to go imo

 

[AP9]

Well I just got a Hayden 678 aux. cooler and will probably get around to installing it this weekend (just in time for cooler weather ). I actually had gone to the junkyard the weekend before last, but most of the Explorers there had transmission coolers that had bent-up fins. I also did see this Crown Vic there:

(http://www.cinewsnow.com/news/local/Peru-K-9-killed-in-crash-218453011.html) and was thinking about taking the trans cooler off that since it looked good still, but figured it would be too wide to fit . . . so given all that combined with the fact that the salvage yard was about to close and I wouldn't be able to make it back for awhile yet, on top of the fact that I didn't want to inadvertently put a "bad" cooler in that would put crap in my tranny, I just decided to buy new.

I've opened up to the possibility of cutting one of the lines as needed, since I figure it would be too much of a pain to have to route an entire hose or hard line all the way from the transmission. I also plan on adding an inline filter at the same time. Anyway, enough rambling.

Would I be able to just fit 11/32" ID hose over the hard line and flare it & add hose clamp? Or are those hard lines not 11/32" OD? For this I don't need to actually buy those fittings that are about $10 apiece, do I?