I think my tranny cooler lines (on a TH350) are switched. Im running an external cooler after my lines go into the radiator to cool the fluid first. Thinking of junking the cooler on the radiator eventually, but for now i would like to use both. Which line is pressure (coming outta the trans)? And does that go into the bottom or top of the radiator. I know i have my lines switched (b/c my tranny sits at the same temp as my water temp). So im assuming im runnig the fluid through the external cooler then through the radiator then back to the tranny. Any help would be appreciated. Thanks guys!!!

Should be in the top, out the bottom, through your cooler then to your radiator. All you have to do is crack open a line and crank over the engine. Have someone watch it. Im sure someone will come along that knows which line is pressure and which is return. (top or bottom on tranny)

Will it really matter if the pressure line goes in the bottom or the top inlet of the radiator???? I was trying to use the shortest length of rubber hose to go from cooler to radiator and i figured it wouldnt matter if the cooler line went in the top or bottom of the radiator. Thanks for the help guys

There are two schools of thought on this, it's been discussed here in the past. One is that the aux cooler should be ahead of the factory cooler because you want to maintain a minimum operating temperature and the engine coolant will ensure that. This method will also help to get the tranny up to temp quicker. The other is that the aux cooler goes after the factory cooler because you want to reject as much heat as you can.

Bottom is out & top return.

but does it matter if i put it in the bottom or top, i just got in an argument about this w/my dad! Any help would be helpful. Thanks. Im gonna run the factory then the aux one in that order. Unless someone has a really good argument. Thanks again

The theory behind Transmission cooling is just a heat exchanger. The actual routing makes no difference. In reading a lot of websites regarding this issue most subscribe to radiator first then aftermarket cooler. Heat is the enemy of the transmission, that is why we have gone to lock up converters as the slipping (torque multiplying) of the torque converter is what creates the heat. The difference in heat that is found from the top of the radiator to the bottom is negligable, in the resevoirs of the radiator, although the bottom is usually cooler as that is where the return line for the engine is. The only problem is that with cross flow radiators, the trans cooling circuit is found in the inlet "hot" resevoir.

Four wheeler.com says:

"Studies show that with automatic transmissions, a 20-degree reduction in fluid temperature can double the life of an automatic transmission. "

and

"We left the inlet side of the line on the radiator and routed the output of that cooler through the Flex-A-Lite cooler for additional cooling."

Thats what im doing, gonna run the radiator cooler to the aux cooler. Thats what i have been doing for quite some time now. But i noticed that the tranny runs at the same temp as the water temp (unless im jackin around). But im just trying to figure out if it will be that much of a problem to run the pressure into the bottom then out through the top to the aux cooler (b/c i will use a lot shorter rubber line) but thats just an idea. I dunno if running the pressure to the bottom then out the top will make that much of a difference if i am running an aux cooler after that. Thanks for the help guys!!!!

Sorry 77cruiser, were you talking about coming outta the tranny?? Bottom is the out (pressure) line and top is the return??? Any thoughts on how much trouble i will be causing by running the line into the bottom of the radiator then out the top to the aux cooler then to the tranny??? Thanks guys!!!

Should be fine.

77cruiser, when you said "Bottom is out & top return." did you mean that the bottom line coming outta the tranny is out (pressure) and the top is return??? Thanks!!!

Yes.

"In reading a lot of websites regarding this issue most subscribe to radiator first then aftermarket cooler"

I've never understood this approach. If you place the aux cooler before the rad cooler it will remove as much as possible because of a greater temp diff consequently loading the rad with less heat. The rad can then remove a bit more. I always put the rad cooler last as a means of keeping the temp as consistent as possible by using the rad as a thermostat of sorts. JMHO.

Well, i switched my cooler lines (i wrapped them in reflective heat wrap a while ago when i first started having this problem when i thought the headers were too close to the lines and they were heating up the fluid in lines). Well....i couldnt tell which line was what due to the wrap, so i switched them anyways. Well, i drove the car all over today, and sure enough it still heated up to around 185* or so. Then i drove it around at like 70-75 mph and it heated up to like 210*.

Im gonna switch them around again!! and see how that works

What is a good opperating temp for a tranny. Just for a side note i have a 3000 rpm stall torque converter in it. Thanks for the help guys. Im a little affraid to take this car too far and ruin the tranny. Thanks for the help!!!

I know that I am a contrary cuss but I'll post this anyway. I have a 2004R transmission installed by Art Carr of Huntington Beach Ca. He uses a special hi flow cooler and does NOT use the radiator. So far after two years of daily driving I've had zero problems with heat.

what temp do you run at???
I have contemplated running just my aux cooler too. Thanks

You should be fine. Transmissions run at those temperatures all day long in production vehicles.

Either use an aux cooler all by itself, or run through the radiator FIRST and then through the aux cooler. If you're not sure which line is which at the trans, click here:

http://tciauto.com/Products/TechInfo/cooler_fittings.asp

Thanks guys. I believe i now really do have my cooler lines switched!! so im gonna re route them and call it good!! Thanks again!!!

Well....here i go posting again!!! I redid my lines again!! And it ran a lot cooler for a while untill i got almost home and it jumped from 180 to ab out 195. not too bad. Here is where my story turns bad.

While driving down the interstate i thought i smelled the sweet smell of burning tranny fluid, didnt think too much of it b/c there was a pos ford infront of me!! Well i got it home to where i store it at my grandmas and was feeling good. When i got back to my house my dad said "any leaks?" and i got worried so i went back up to look at the car and sure as $hit it was leaking!! I started it up and its a slow trickel from the line that goes into the radiator. I took it out and the threads on the line look ok. And it went in fine. I put it back in and it is still leaking.

Maybe time to get that aluminium radiator from summit (the that has no provisions for a tranny cooler, and then do the steel braided line i have been thinking about for a while??