transmission cooling questions

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pjc360

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I have a fresh non lock up A-518 trans in my 91 4wd truck and i need to know if what i have is enough to keep the trans running cool.
The guys at the transmission shop that re-built the trans told me that the transmission cooler on the radiator was plugged so bad that 150 psi of air off there air compressor wouldnt even blow it out. I dont know if this true, i think they wanted to sell me the cooler they did because it was an extra 100 bucks or more.
But anyways i have a cooler mounted on the outside of my radiator, its not huge but not real small ether, i'd consider a mid size or aavereage sized cooler, the other day i read that you should have the fluid circulating thru the radiator part first then thru an axuilary cooler, how true is this? Is the cooler i have mounted on my radiator not enough to keep the transmission cool?
And if not, how would i run this set up? how would i get the fluid going thru the factory radiator cooler and then on up to the cooler the transmission shop gave me? The guy at the transmission shop aid the cooler they gave me would be enough to keep it cool, but i read never to run just a axuliary cooler.
 
Well, get a trans temp gauge. That would tell you what it's doing.

As far as the cooler built into the radiator, if it's plugged, you can't use it. Nothing would flow through it.

One thing you could do is blow some air through it yourself and see if it's plugged or not.
 
................i would still replace the cooler in the rad or get a new rad, prolly could use it anyways.......i cant believe they let u out of the shop like that, especially if their gonna warranty it.......kim......
 
..most any small external cooler is probably fine...you want the trans at 180 or so.
..passing the fluid through the rad heats your fluid for cold weather operation.
unless you're racing or towing,you probably shouldn't use a large cooler
 
I was told that passing the fluid thru the radiator was a cooling technique??? I had no idea it was meant to warm the fluid? I see where the transmission fluid lines are on the radiator, i will try and blow some air thru there to see if its really plugged or not.
I hope its not plugged tho, i like the radiator i have, my engine never gets above 195 and i dont even have a fan shroud ether, but lot that could be my fan i guess.
I think its a brass radiator?
So if the fluid going thru the radiator is just to warm the fluid, then i wouldnt really need it? because when its cold outside i let the engine idle for a good 5 minutes before i even drive it and i let it idle in nuetral so the fluid circulates thru the tranny.
But i was told and i read online at a transmission web site that te fluid passing thru the radiator is a cooling technique.
They said if you were trying to cool a hot piece of metal would you put it in water or in the air? So it made sense to me, they said an axuilary air cooler is not enough to cool the transmission, and that the radiator cooler part is critical, but the owner of the transmission shop that did my transmission told me i'd be fine with the cooler they gave me?
So i dont really know??? But on that transmission web site they said radiator cooler is critical and if you ant to add an additional axuliary cooler then great because that will help too. they made it very clear that you have to have the fluid circulate thru the radiator and then up to an air cooler if you have one and then out of the air cooler into the transmision.
So it would go thru the radiator first then thru the air cooler and then out from the air cooler (axuliary cooler) to the transmission.
So the way my radiator is, if its not plugged, i think i can take the hose off my auxilary cooler and hook it to where it enters into the radiator, and then get a new hose to put where the fluid exits the radiator and have the hose plug into where the fluid would enter the auxilary cooler.
I wish i could post a picture of what my radiator tranny cooler looks like... its at the very bottom of the transmission and has a place for a hose to enter on the bottom of the radiator by the drivers side, then another place for a hose to go on the bottom of the passenger side.. i'm assuming the fluid would enter the radiator on the drivers side bottom then come out on the passenger side bottom... Correct?
 
I have an finned aluminum deep sump transmission pan that was recommended by Harold at Dynamic transmissions many years back. Although I run a 727, the temperature never exceeds 180. I have little room to put any cooler anywhere. If I were to run a cooler, I would get one with a fan attached to it, steep on price but worth the money from what I've been told. Gets over 100 degrees here in the summer months so I may get one of those for security.
 
the trans portion is an 8" double walled 1/2 tube in the bottom tank.How can passing fluid through a 180 degree rad cool the fluid?
you will need this for cool weather operation because your trans will not get warm enough on its own.
for warm weather the aux cooler is a good idea.
 
Actually the trans cooler does both.
It warms the fluid when cold and cools the fluid when it's warm.
Running ONLY an auxillary cooler on a 4x4 is not a good idea because in 4x4's there are a lot of times that there is not sufficient air flow to cool the trans.
Just sitting in gear the converter generates quite a bit of heat on it's own.
With an auxillary cooler only, a fan would be needed (On a 4x4) but the best would be rad and auxillary both, or auxillary with a fan and temp guage.

Now get this.
If you put the auxillary cooler before the radiator (flow wise) then the cooler will help cool the engine and the trans (because of the tubes in the radiator)
If you put the auxillary cooler after the rad then ALL available cooling from the auxillary cooler goes to the trans.

Make sence?
 
Trailbeast..you make some good points.
the bottom tank would probably be 150 - 160 or so and would have some cooling effect if trans was at 180 or so.
there is just one double wall tube in the bottom rad tank, and is only about 8" long in some of these old rads.
 
You do not have to flow through the radiator cooler as a rule. Some vehicles only have a fluid to air cooler stock so its not required at all. If the tranny shop said the cooler in the rad is clogged don't use it. The cooler circuit flows back to the tranny and lubes all the internals. If you restrict the flow you will wipe out the OD unit on the 518 in no time. Any junk that is trapped in there clogging it up will ended up back in your tranny. Grab the lines in and out of the cooler or shoot them with a temp gun see what your temps are like then decide if you need to do anything. Coolers and radiators are cheap trannies are expensive so keep it cool.
 
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