Automatic Transmission
Cooler Lines
Authored by Wes Vann, Created on July 4, 2001
Preliminary!!!!
PLEASE NOTE; Always use jack stands when working under the car!
When I built my 64 Chevelle wagon, I put in a 350 engine and TH350 transmission. What I did at that time for the transmission cooler lines was to run stainless hard lines from the radiator, along the inner fender panel and then to a bracket with bulkhead fittings. From that, I had rubber hose connecting to the transmission. All the fittings were #6 AN. Due to having the rubber section, I could remove the engine or transmission without having to bend the hard line. It worked well, except after the suspension settled (I put in new springs), the upper control arm rubbed the hard line. (I ran it that way and it never did rub through the stainless hard-line!) I also wanted a cleaner engine compartment and felt that the lines could be routed next to the engine oil pan similar to what the factory does.
I didn't want to run solid hard lines from the radiator to the transmission due to "serviceability" as noted above. That meant that there would be flex sections near the transmission and also flex sections going to the radiator (due to the moving around of the engine on it's mounts).
This "tecref" is the result of what I did.
Most of the photos will be "clickable" to a larger version.
The reason that I'm showing this photo now is so that you can get an idea of what I was after. It's a "mock-up" engine (piece of junk) that is sitting upside down. On the left side are the hook-ups that would go to the radiator. The are spaced apart to help clear the harmonic balancer. The fittings shown on the right are the lines that would go to the transmission. Note that there are 45 degree fittings shown and that is close to what the finished lines were. The finished, installed line goes upward and around the torque converter cover.
In this photo, you can see the two brackets that are mounted to the front of the engine. The one that is on the left is a simple piece of flat stock with a 90 degree bend in it. It's bolted to the block with one of the threaded holes that don't ever seem to be used. (I have no idea why Chevy has them!!)
The hole that is in the bracket is where the hard line will go and is positioned so that the hard line will clear the back of the harmonic balancer.
Here you can see the other bracket. It's also bolted to the block using one of the threaded holes there.
If you look close, you will notice that I marked on the oil pan the dimensions "5"". What I was doing is trying to keep in mind that I wanted the hard lines to end up about 5 inches from the crank centerline. This would result in them lining up fairly well with the inputs to the radiator.
Here is an interesting fact that every small block owner should know; There are two threaded holes in the location where this bracket is bolted. (keep in mind that the engine shown is upside down) I'm using the lower one. The upper one actually goes to the fuel pump push rod and if you put too long a bolt there it will hit the fuel pump push rod!!!!! If you don't put a bolt there, it will leak oil!!!
This photo shows the bracket that I made up that mounts at the rear of the engine.
I'm using one of the oil pan bolts to attach it. Now this is REAL important, It's not really attached using a bolt! What I've done is make up a stud for that position. There is a nut that tightens down the oil pan. Then the bracket is put in place. Then another nut is added to hold the bracket.
This bracket was made out of flat stock also and took quite a fair amount of time. Keep in mind that no part of the bracket can go beyond the rear surface of the engine or it would hit the torque converter cover.
Here you can also see that I mounted a starter in order to verify that everything will clear. That leads up to another fact that is helpful to know; The starters for the larger diameter flex plates mount farther away from the side of the oil pan than the starters for the smaller diameter flex plates. Where this can really make a difference is the fact that the starters for a large diameter flex plate would be closer to your headers, and all the heat that they put out!!!!
This photo shows the hard line in place and brazed to the brackets. That "funny" little step in the lower line, on the right, is just due to the angle that I took the photo.
The hard line is made out of stainless due to my wanting the extra strength
that it offers. Before bending the costly stuff, I did test bend with a bunch of
cheap "bundy flex" that I got from Kragen. Some people will recommend
that you work out all the bends using welding rod, but I'd rather spend a little
more and use cheap soft metal line of the same diameter. Yes, I end up with a
trash can full of hopelessly bent up line.
Here you can see where I've cut off the extra length of line and brazed on the #6 AN fittings. The same type of line ends were brazed at the other end.
These are the end fittings that were used. I purchased them as shown. If you can't buy them like this, get steel "bulkhead" fittings, cut off the un-needed section, and drill in a shoulder to fit the hard line.
If you were worried about looks, the thing to do is "silver solder" the fitting on. This gives a better look. I just brazed them on.
Here I'm done with the fabricating.
Before going any farther, you should check all the fittings for leaks!! What I did was mount the assembly in a vise, fill the line with lacquer thinner and then pressurize it. I had leaks!! They were real small, but none the less, they were leaks. After re-brazing a couple spots, everything checked out ok.
Installing the assembly;
Well, it would be a piece of cake to mount on the engine if it was out of the car, but I really didn't want to pull the engine at this time.
During a (rare) free week-end I got to looking at it and decided to give it a try.
I had to pull the starter, torque converter cover, and lift the engine a couple inches, but I managed to lace in in position. Then I had to remove the stud (I had installed oil pan studs prior) at that rear corner of the pan so that I could add a longer one. That done, the assembly bolted in position.
Now to be technically correct; the starter has to be bolted in before the line assembly. What this means is that if I have to replace the starter, I will have to first drop down the line assembly. I wouldn't have to remove the hoses from it!
At this point, I could make up the flex hose lines.
Due to the prior installation, I already had adapters at both the radiator and transmission for #6 AN fittings.
This photo shows the two lines that go from the "assembly" to the radiator.
The hose is Aeroquip 3/8" "FC332" and is rated for 250 psi. The fittings are #6 AN "push-ons". These fittings do not require a clamp! (at least not at the pressure an automatic transmission will put out)
I could have also made the lines out of braided stainless hose, but there is no reason to spend the money. Another reason is that should there be any problem with heat from the headers damaging the hose, I'd be able to see it before the line blows out. The only real reason to run braided stainless hose (in this case) would be if you were worried about rubbing on something.
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