Transmission lines - which goes where?

[FL71C10]

I am putting transmission cooling lines in my truck, but I can't tell which line goes in the top transmsission fitting. It's a 350 engine with TH350 trans. Does it matter which is which?

Thanks!

[Critter]

I've always put the bottom line to the bottom of the radiator/cooler, top to top. You are probably just going straight to your radiator with both, but here is a similar diagram showing an auxiliary cooler.

[ETsC10]

Great answer Critter! Right-click-save






.

[mrein3]

Be careful if you live in a cold climate. That picture is BACKWARDS for those of us up north. In the winter that diagram might have you returning tranny fluid that is too cold to your transmission.

Up here you route hot fluid to the external cooler first. Then to the radiator to heat it up some when it is -20 outside.

I like to post this disclaimer every time we talk external transmission coolers. I'd hate to see somebody in Moose Jaw, Saskatchewan hook their new $1500 700r4 like some southern boy then wreck it with cold tranny fluid.

[FL71C10]

so, what do you when it gets real hot?

[mrein3]

Originally Posted by FL71C10

so, what do you when it gets real hot?

Nothing. It doesn't get real hot. I've never seen my trans temp gauge go over 215 in the heat of summer pulling the heaviest thing I regularily pull.

[FL71C10]

I guess switching the lines only affects the pre-heating effect, as the radiator should never go over a certain temp unless it's failing or the fan is broken.

[Critter]

Originally Posted by mrein3

Be careful if you live in a cold climate. That picture is BACKWARDS for those of us up north. In the winter that diagram might have you returning tranny fluid that is too cold to your transmission.

Up here you route hot fluid to the external cooler first. Then to the radiator to heat it up some when it is -20 outside.

I like to post this disclaimer every time we talk external transmission coolers. I'd hate to see somebody in Moose Jaw, Saskatchewan hook their new $1500 700r4 like some southern boy then wreck it with cold tranny fluid.

Ok, if you would have said my little diagram was totally wrong/backwards I wouldn't have argued at all, its possible it is wrong. BUT you are telling me that trans cooler lines need to be connected one way for one climate, and the opposite way for another??? I find it hard to believe that Chevy (or ford or dodge or etc) would have manufactured them one way for the north and one way for the south. So if the manufacturer didn't have to produce two different ways, I don't think we would have to. I'm not saying your necesarrily wrong, it just goes against everything I know about mass produced vehicles...which isn't everything...but it's a little. Can you elaborate or tell me where I am wrong?

[mrein3]

Originally Posted by Critter

Ok, if you would have said my little diagram was totally wrong/backwards I wouldn't have argued at all, its possible it is wrong. BUT you are telling me that trans cooler lines need to be connected one way for one climate, and the opposite way for another??? I find it hard to believe that Chevy (or ford or dodge or etc) would have manufactured them one way for the north and one way for the south. So if the manufacturer didn't have to produce two different ways, I don't think we would have to. I'm not saying your necesarrily wrong, it just goes against everything I know about mass produced vehicles...which isn't everything...but it's a little. Can you elaborate or tell me where I am wrong?

I didn't say your diagram was wrong. I'm just pointing out that there is a better way to route hot tranny fluid in colder climates. While my truck rarely if ever is driven in temps over 90 degrees, I doubt your truck ever gets driven in -28 degree (not wind chill, ambient temp) weather like mine was two weeks ago coming across the lake after an evening of ice fishing. That evening it got to -32 on my mercury thermometer. 130 degrees colder than a typical hot Texas day.

Of your mass produced vehicles, how many vehicles on the lot right now around Bulverde, TX come with block heaters? I was recently shopping for a new car. I'm leaning towards the Ford Edge. The closest dealer is Anderson/Koch in North Branch, MN. On my list of must haves if I buy off the lot verses ordering is a block heater. EVERY Edge on their lot comes with a block heater.

My '04 Explorer came with an external transmission cooler. I never bothered to see how it was plumbed. It works and I don't care. I doubt Ford routes them one way for up here and another way for down there. However, if there is a better way to do something on a car/truck YOU are building (not mass producing), why wouldn't you do it the better way?

Even better than routing it one way down there and one way up here is to put an "H" in the lines with a couple of shut off valves. By opening and closing valves you could route it one way in the winter and one way in the summer. In fact I know a really anal guy that does just that. Even better than that, one could dream up a thermostat controlled line system where NONE of the fluid goes to the radiator or external cooler until it warms up.

Alas simplicity usually wins out. No "H"es, no valves, just route it your way down south and my way up north and all is good.

[eagleuh1]

How about quick connect hoses you could switch around.

[Critter]

Originally Posted by mrein3

I didn't say your diagram was wrong. I'm just pointing out that there is a better way to route hot tranny fluid in colder climates. While my truck rarely if ever is driven in temps over 90 degrees, I doubt your truck ever gets driven in -28 degree (not wind chill, ambient temp) weather like mine was two weeks ago coming across the lake after an evening of ice fishing. That evening it got to -32 on my mercury thermometer. 130 degrees colder than a typical hot Texas day.

Of your mass produced vehicles, how many vehicles on the lot right now around Bulverde, TX come with block heaters? I was recently shopping for a new car. I'm leaning towards the Ford Edge. The closest dealer is Anderson/Koch in North Branch, MN. On my list of must haves if I buy off the lot verses ordering is a block heater. EVERY Edge on their lot comes with a block heater.

My '04 Explorer came with an external transmission cooler. I never bothered to see how it was plumbed. It works and I don't care. I doubt Ford routes them one way for up here and another way for down there. However, if there is a better way to do something on a car/truck YOU are building (not mass producing), why wouldn't you do it the better way?

Even better than routing it one way down there and one way up here is to put an "H" in the lines with a couple of shut off valves. By opening and closing valves you could route it one way in the winter and one way in the summer. In fact I know a really anal guy that does just that. Even better than that, one could dream up a thermostat controlled line system where NONE of the fluid goes to the radiator or external cooler until it warms up.

Alas simplicity usually wins out. No "H"es, no valves, just route it your way down south and my way up north and all is good.

Ok, I see your theory. I still have a mental hang-up with it from a production point of view but I guess that's MY problem. As a side note, it's been as low as 10 deg (ambient not wind chill) here the last two winters in a row and diesel vehicles (a large % of trucks) in the area usually come with block heaters. As another side note...-32 is way too cold for fishing!

[mrein3]

Originally Posted by Critter

Ok, I see your theory. I still have a mental hang-up with it from a production point of view but I guess that's MY problem. As a side note, it's been as low as 10 deg (ambient not wind chill) here the last two winters in a row and diesel vehicles (a large % of trucks) in the area usually come with block heaters. As another side note...-32 is way too cold for fishing!

You are right. That is why I was sitting in front of my 22" flat screen in my heated fish house. DirectTV comes in quite nice from the middle of a lake. Besides it didn't get that cold until later after I was home.

-20 something is so cold that you have to keep your beers inside to keep them from feezing.

[67swb72klb]

-20 something is so cold that you have to keep your beers inside to keep them from feezing
or u could bring the cooler to keep them warm

[LostMy65]

Saved for later reference....

[Davidf]

This tread has me thinking: Did GM even offer the trans coolers as an option? If so, I imagine it was intended only for hot climate regions. I agree that cold trans fluid is not so great. Also, on modern cars that have trans oil coolers separate from the radiator (and even the ones that flow just through the radiator in some cases...BMW for example) the trans cooler is thermostatically controlled for faster warming of fluid and to prevent excess cooling. This way, it works properly in all climates. The danger of the thermostatically controlled through the radiator only coolers is that if the thermostat fails closed, you can cook the fluid and damage the transmission...