?? External transmission cooler question

[1970 Custom Camper]

I have a stock C-20 CC with a 350 and TH-350. It has an aftermarket external transmission cooler mounted under the radiator. I am replacing the radiator. The factory transmission line fittings at the radiator are pretty buggered up from being taken off and put back on with the wrong wrenches. My question is, do I need to re connect the transmission lines to the factory radiator trans cooler, or is having the external cooler sufficient? Thanks for sharing your opinion

[truckdude239]

the external is good but it needs to be in front of the radiator to aloow air flow across it not under it

[1970 Custom Camper]

Originally Posted by truckdude239

the external is good but it needs to be in front of the radiator to aloow air flow across it not under it

It is actually mounted under the radiator with clear frontal area and a scoop/shroud around it. I guess I should post some pictures, huh? lol

[1970 Custom Camper]

[cdowns]

the radiator allows the fluid to b at the optimal operating temp// too cool dont get a prize

[Tim240Z]

Also, by not having it in front of the radiator and going through the radiator cooler core, you get no cooling at low speeds....I just found that out....
The way yours is placed (somewhat similar to how I had mine), you get no air flow from the engine fan when not moving, and no cooling help from the radiator.....

Here is my recent post, where I put everything back to how it was supposed to be.....
http://67-72chevytrucks.com/vboard/s...d.php?t=500760
New trans cooling lines are not expensive, so if your fittings are messed up, just buy a couple more lines (5/16th) and bend to match. If you don't have a tubing bender, you can make gentle bends by hand.......just don't try to make sharp bends....

[1970 Custom Camper]

Originally Posted by cdowns

the radiator allows the fluid to b at the optimal operating temp// too cool dont get a prize

I understand what you are saying. Thanks!

Originally Posted by Tim240Z

Also, by not having it in front of the radiator and going through the radiator cooler core, you get no cooling at low speeds....I just found that out....
The way yours is placed (somewhat similar to how I had mine), you get no air flow from the engine fan when not moving, and no cooling help from the radiator.....

Here is my recent post, where I put everything back to how it was supposed to be.....
http://67-72chevytrucks.com/vboard/s...d.php?t=500760
New trans cooling lines are not expensive, so if your fittings are messed up, just buy a couple more lines (5/16th) and bend to match. If you don't have a tubing bender, you can make gentle bends by hand.......just don't try to make sharp bends....

That makes sense to me. I guess I'll relocate it to in front of the AC condenser and get some new lines or fittings at least.
Thanks!

[1970 Custom Camper]

I sought some advice from a regional fleet service manager for GM that I know from air forums.com about transmission cooling. He said;

"Lance,

There are about a dozen ways to skin this cat.

I'll skip a lot of the lengthy reasons why, in case you already know the reasons. If you have any whys, ask and I'll fill in the blanks.

What I'd do:

Install HEAVY DUTY TOWING radiator with internal trans cooler.

Since you already have an external, like you said, move into the fan draft and plumb it in line with the internal cooler. Ie. Fluid from trans into internal cooler, output from internal to external. Out of external back to trans.

I would install a deep sump trans pan WITH a fitting for a trans temp gauge. Install gauge in cab.

I'd try this setup and monitor temps while towing. Ideal is to keep it below 200* on the flats. Temporary peaks up to 220* while climbing grades is normal. I start getting nervous if I see above 230* for any length of time. Trans fluid starts to oxidize at 230* and oxidizes at a faster rate at higher temps. At 300* your trans wil last about 15 minutes. These are sump temps.

If you consistently see above 200 on the flats I'll recommend a different external cooler. I don't think we can link to websites on PMs. Send you email and I'll send a link to a really nice fan cooled external cooler. It is the unit I think I'l put on my van if I have to force it into overloaded severe service. Which it would be pulling my 30'er."

So I relocated the cooler in front of the AC condenser. Plumbed it as he suggested above and now I'm on to looking for a trans pan that has a bung for the temp sender. I would like a finned aluminum pan with a temp probe bung but I'm not having luck finding one. The only one I could find was a Derale cooling pan. I'm not sure if this will clear the cross member. Have any of you installed a deep pan?

[storm9c1]

I used to believe in deep pans until a trans shop that I trust told me that using deep pans is risky, especially if they do not have support for the filter. Deep pans with no support for the filter could allow the filter to come loose. If it comes a little loose, it will introduce air bubbles into the system (bad). If the filter completely falls down, you will come to an abrupt stop (and probably burn your clutches in the process). So keep this in mind when choosing a pan. Over the years, I've seen a few higher priced ones for various transmissions have a method of support for the filter. But most don't.

I used to to use a Derale pan (the one with the cooling pipes) and it did properly support the filter since the filter rested on the cooling pipes internally. This was for a 4L60E. After about 10 years though, that pan developed a leak around one of the welds for the cooling pipes.

I have no idea about the cross member. Every truck/combo is different. Shouldn't be hard to tell by crawling under and seeing how much clearance you have around the trans. Keep in mind that deep pans hang down lower too and can bottom out depending on what you do with your truck.

[Tim240Z]

I installed the sender unit for the trans temp gauge into my stock pan. I drilled a hole slightly smaller than the sender, then just screwed it in....it doesn't leak at all and always sits in fluid. Obviously, you need to pull the pan and find a place that the sender won't interfere with anything on the inside.....

[fastwillie 696969]

most deep pans comes with a filler tube extension adapter .i love mine

[Dunenutt]

I used this one. I drilled and tapped for 1/8 in pipe, into the drivers side. Works great!

http://www.summitracing.com/parts/SUM-433884/

[gofastnut]

You can pick up different sizes and lengths of brake lines @ any auto parts store. Figure out the length you need, then off you go. You could always take a shorter brake line (18") cut in half and have two connectors to go to pressure hose if you wanted to. Just make sure to clean and single flair the ends to keep the line from coming off.