3 years ago when I installed my trans cooler I spliced into the stock trans cooler line coming out of the bottom of the radiator, then into my B&M cooler.

I really didn't give it much thought, for some reason I was sure the bottom stock line was the return line. BUT, after reading some stuff it seems that the top stock line coming from the top of the radiator is the actual return line. So the ideal way to hook up the cooler would then be to splice into the top line thus sending the fluid through the aftermarket cooler AFTER the stock cooler.

So I need the FINAL answer here... which line is the return line? The top line? Is the top line what everyone is using for their coolers?

PS. I've already switched the cooler to the top line as it seems that is the correct way, but I'd like to confirm once and for all....

 

Ryan, I have always wondered the same thing. I did alot of research trying to figure it out when I put mine on 2 years ago. I never got the DEFINITE answer though. The TRUE answer probably will come from someone that knows the 4L60E:

Which fitting on the tranny case is OUT and which is IN?

Chuck (FLP) could probably tell you. If you talk to him and he knows be sure to let us all know!!

 

Hi Chris

You know, I was just at FLP about a month ago and I didn't even think to ask. I should have.

The on-line install guide I've seen says that the top line is the return line, but I want to get solid answer.

 

Nobody knows?

 

When i did mine i had the same problem. Actually i don't have any lines directly connected to the stock cooler from the B&M Supercooler. The top line is the return line. Bottom line is the trans to the cooler line.

 

How did you run your B&M lines then? Just wondering how you set that up?

So the top line is the return line, that's what I was leaning towrds. You're talking about the top line on the radiator, correct? That's the one to use?

 

I used the B&M and the stock cooler. connected the top stock line to another line to my B&M then connected the other line from the B&M to the top hole on the stock cooler, works great. I only assumed it was the return, otherwise that POS slip fitting of the hose onto the metal at the bottom w/ a clip wouldnt stay on at high pressure

 

Why would the pressure be much different leaving the trans or going back into the trans? I never thought there would be any difference?

BTW, I had the cooler hooked up to the bottom line (apperently the out-of-trans line) for 3 years and it never leaked with just hose clamps on the B&M hose. I now have a piece of rubber trans line there again with clamps and there is no leak (I did use strong clamps well tightened though)...

 

Final answer. The Top line on the radiator/trans cooler is the return line. If you bought a new B&M super cooler rated at 24,000 gvw; these instructions would have been in the box. It is a simple hookup and all parts are included in the box.

 

Well what i did and what i thought was the correct way was to connect the hose that was originally connected to metal tube with a hose clamp, to the hose to the supercooler by using one of the supplied metal adapters. Then i connected another hose from the supercooler to the metal tube and clamped it down with a hose clamp. I might have said this backwards but i know i have it running through the supercooler after it runs through the stock cooler. I guess that finally know and now that i understand it fully i'll probably change it.

 

Why would you chnage it?

It sounds like this is the correct way, and that's exactly the way I have mine setup now.

As far as the B&M instructions stating which line is the return line, I actually was able to find my instruction sheet from years back, and it did not list 4L60E info. However it did list 700R4 and 4L80E I would guess that the 700R4 info would be the same as a 4L60E....

 

So we all agree that the top line on the radiator/stock cooler is the return line, correct?