700R4 Cooling lines

[Dignan]

What type of fitting does the 700R4 use for the cooling lines? I have a 700R4 in my 91 Explorer, I have a leak in my cooling line adapters. I don't know if the guy cross-threaded it or what, but I am thinking of running new lines from the tranny to a new cooler so that Moab or just bumper to bumper on the highway doesn't toast it. I'm sure that the stock cooler is pretty decent, but I want one with a fan on it, so I'm thinking it will be easier/better to re-plumb the tranny's cooling system. Any ideas on the subject?

 

[Maniak]

I'll have to look at what kind of fittings are on my 700r4. I do know I go from hard lines to rubber towards the front and the Top line is the return from cooler while the Bottom line is the out from the transmision.

As for the cooler.. If you already have a decent cooler, get a fan from Geo Prism (same as toyota corolla).. It a 10" fan that pushes some serious air. It was easy to build a bracket to hold it and I have it mounted right in front of the cooler. It has a metal shroud and a metal cage in front of it to help keep crap from going into it.

~Mark

 

[Maniak]

According to TCI the fittings (upper/lower) are both 1/4" Pipe thread.
http://www.tciauto.com/Products/TechInfo/cooler_fittings.asp

Wikipedia also says they are 1/4" pipe thread...http://en.wikipedia.org/wiki/Turbo-Hydramatic#700R4_.2F_4L60

~Mark

 

[Dignan]

Does the cooler really need to be up front? I was thinking of putting it the area which was formerly occupied by the spare tire. Does it need the direct air from the front? In moab that isn't really a lot of air at those slow speeds, so I figure it is just as effective anywhere with a fan as long as there is airflow on both sides of the cooler, right? Anybody have some crazy, but effective ideas for this? I don't want to do anything ridiculous, but I'm open to other options.

 

[Maniak]

The cooler up front will push air through it when your moving. You can put it anywhere, just make sure air goes through it. If you put it where the spare tire was you need to make sure it doesn't get whacked by a rock, but a fan on it would get air flowing through it. Also, with it down low like that it is possible for it to get full of dirt/mud etc and then not flow at all (which is why I didn't take my cooler off the front).

~Mark

 

[Dignan]

I was figuring I would need a skidplate, but I didn't think about mud. I don't do a lot of serious mudding, but you never know. Hmmm, I'm still thinking about other ways to do it, but I'll probably just end up leaving it where it is.

 

[Dignan]

What is the best way to connect a rubber line to a metal line? Are the cheesey looking little clips that came stock ok? or is there a better way?

 

[Maniak]

I know I"m not doing it quite right.. I'm just double clamping them (hose clamps). Propper is to flare them and then put a rubber hose on them, but I have 50k miles on the lines the way they are now (just double clamped)

~Mark

 

[Dignan]

Theoretically if the correct way to do it is to flare it, would the stock hard lines then be flared? Because if I leave it in the front, I will not replace the hard lines, just the rubber hoses. If the stock hard lines are already flared, it should be rather simple to just get a 1/4" fitting for the tranny and the rubber to the hard line and then new rubber for the end of the hard line to tranny (in and out on both ends of course), with some new clamps, it should be rather easy.

 

[Dignan]

So, I finally crawled under there. It looks like the guy that put in the tranny used a hard line coming out of the tranny, and then an adapter to the fittings from the A4LD. It is the fittings that join old and new that is leaking. So my question is this. Is there a great benefit to the hard lines at the tranny? If not, it sounds a lot easier to me to just cut off the line including those fittings and flare it, then run a rubber tube to a fitting like this....
http://store.summitracing.com/partd...924496+4294839052+4294842008+115&autoview=sku
I will look for a fitting with a 90 degree angle so that I don't kink the rubber hose, but this seems to be an easy fix. Is there any reason to not do it this way?

 

[Maniak]

The real advantage for the hard line is that it should last longer then the rubber line. Thats a line that you will problably forget about and then one days, years from now it will burst.. Other than that, I don't see any issues with the rubber lines (assuming you use Trans cooler lines, and not thin rubber hose).

~Mark

 

[BrooklynBay]

If it is a brass adapter with threads which is leaking, you could take it apart, and then repack it with teflon tape. Don't put too much on it. You wouldn't want to get any of that tape into the lines. It could cause a clog somewhere. Maybe a small amount of pipe dope would also work on the threads.

 

[Dignan]

Mark, thanks again for a good answer. I would hate to dump my tranny fluid as I'm going down the freeway, or in the middle of a trail or something.

Good idea Brooklyn, I guess I assumed it was cross thread because it is leaking pretty badly, but I guess with the pressure, even a small leak through the teflon tape can add up quickly.

I'll try to stop the leak in the fittings before I cut it up and redo it. I'm not sure when I'll have time to do it, but I'll let you guys now how it goes. Then it will be on the the fan, so that the Moab heat wont toast my tranny. Mark, is there a specific year range on those geo prizm fans that you were talking about? If not, thats ok, I'll just go look for one that is about the right size. Also, did you hook up a thermal switch or just run it all the time, or put in an on/off switch and just watch the temp gauge?

 

[Maniak]

Its the year the Geo Storm was the same car as the corolla. It should be 1993-1997.

I attached a pic of it.. It is an all metal fan. Blades are metal, shroud is metal and even the guard is metal..

I'm using some relays to control the fan (and a capacitor)..

Basically, When the trans is in lockup I use a relay to charge a 38,000 mfd capacitor. That capacitor is in paralell to another relay. On that relay I have it controlling the fan on the normally open contact. That way when the trans is no longer locked, the capacitor keeps the fan from turning on until the cap is discharged (about 5-8 seconds). This way when I just tap the brakes or something similar the fan doesn't turn on right away. After the 5-8 seconds it send power through the normally closed connection on the 2nd relay which then controls the relay that runs the fan.

I know it sounds kinda complicated.. If you want, I can draw it out. It seems to work well.. I am going to add a couple 12V led style lights to the circuit so I can tell when the fan "should" be on, and if the fan is really on.

~Mark

 

[Dignan]

That's a little bigger than I had pictured in my head. Does it help with the engine cooling as well? I was thinking about replacing my clutch fan with an electric puller fan, but maybe if I had that fan pushing, it would let me postpone that project. I tried to do this last time I was in Moab and my A4LD overheated, but the fan that I bought was too big and has since been scrapped. Did you have any trouble fitting that fan?

 

[Maniak]

Its really not that big.. I just zoomed in on that pic.. thats just the right side of the grill.

The grill does touch/push a little on the fan, but no biggie. I just bent some scrap 1" by 1/8" metal to make a couple brackets to hold it in..

I don't know if it helps cools the truck.. I doubt it.. Not because of the fan, but because its blowing on a trans cooler that is in front of another trans cooler that is in front of the a/c condensor that is in front of the radiator.

My plan is to remove both trans coolers I have in there now and replace them with a single 1.5" thick 10" across 18" tall one. that way 1/2 of the radiator is still only covered by the a/c condensor, and won't have anything in front of it which should help keep the truck cooler.

I have attached the unzoomed pic so you can get a better idea of the size.

~Mark

 

[Dignan]

oh yeah, from that perspective it looks a lot smaller. Maybe I'll just get two and put one on both sides and the other one will help the engine keep cool. It would be a lot cheaper than a new fan on the back. As far a wiring, that does sound a little complicated. Couldn't I just hook up a temp sensor to turn it on when its hot and leave it off if its not hot?

 

[Maniak]

Yes, you could use a temp sensor. I didn't because my pan temp is 130F even before I start the truck in the summer.

Once the fluid gets hot, it takes a while for it to cool off and I don't want to have to set my fan at a high temp to keep it from running most of the time (I do 60 miles/day on the freeway and dont' want it running when I'm on the freeway).

I figure if its running on the freeway it is hurting the cooling capacity, so now it only runs when I'm < 45mph, regardless of the temp.

~Mark

 

[Dignan]

Ok, I went back and read through your explanation of the circuit. Let me see if I'm on the same page as you. You don't want it on while driving on the freeway so being wired to the TC lockup, the fan will turn off when the tc locks up, which is basically at highway speeds. The capacitor keeps the fan from coming on immediately to give the tc a chance to lockup again when braking, to again keep the fan off. Am I way off on this? If that is what your circuit is doing, it sounds good to me. Could you get me a drawing of the circuit?

 

[Maniak]

Ok, I went back and read through your explanation of the circuit. Let me see if I'm on the same page as you. You don't want it on while driving on the freeway so being wired to the TC lockup, the fan will turn off when the tc locks up, which is basically at highway speeds. The capacitor keeps the fan from coming on immediately to give the tc a chance to lockup again when braking, to again keep the fan off. Am I way off on this? If that is what your circuit is doing, it sounds good to me. Could you get me a drawing of the circuit?

You have it exactly.. I'm using a few relays to do this so it only runs when the truck is on and TC isn't locked AND so the capacitor isn't being charged directly by the TC lockup circuit..

I'll try to draw it up tonight.. (I might even have my original drawing)..

~Mark