Thread: Transmission Cooler

Tweet

I am sorry to see some valuable experienced folks drop out but I am still sitting in my garage looking at parts in considerable frustration. The topic here is that I have a 700R4 installed in my Brookville Model A frame and just finished installing a battery box in a somewhat unusual position on the back of the horizontal bend around the back of the pumpkin. This frees up the entire right side frame rail for some other stuff. In particular I have looked at every catalog I can find to look at transmission coolers since my '29 radiator does not have a trans cooler. In addition Henry Rifle sent me a small cooler which may be too small since he went to a larger one. The problem is the coolers with fragile aluminum fins are likely to get bent up from flying rocks on a gravel road and if I mount it on the right frame rail it will be right above the exhaust pipe, not exactly a cool place for heat exchange. I favor the plate-style coolers for ruggedness rather than the fin type but everwhere along the right frame rail there will be heat from the exhaust system. Another problem is that I would think it would be a good idea to put the cooler into the air stream under the car, but almost all the coolers I have looked at would be mounted to the frame flat against the frame and sideways to the air flow? All of this is made worse if I use turbo offset mufflers. A while back Tech1 suggested using cylindrical glass pack mufflers mounted straight thru but with the muffler reversed to use the interior louvers backwards for more sound deadening. Small diameter non-offset mufflers might give more separation between a cooler and a hot muffler but even so it is tight under there! Any suggestions?

Don Shillady
Retired Scientist/teen rodder

run 2 "L" brackets off of the trans. pan bolts and mount the trans cooler up the side of the trans. should get some good air there.

Don't lay it flat, a friend of mine cooked his C4 that way.

Hey Don, welcome to the world of "A" Bones. Now you know why they are called HOTRODS! You should really look into a radiator with trans cooler installed. I run a Walker radiator with a built in cooler and also use a B&M trans cooler mounted at an angle agianst the 4 bar crossmember. The 700R4 needs to stay under 200 degrees. For every 20 degrees above 200, the life of the trans is cut in half. Trans life is around 200K miles. So temp is very important.

Don, one other consideration would be an inline cooler mounted vertically on the radiator bracket, alongside the radiator where it would be exposed to some good airflow. As tight as things get on an "A" front end, perhaps an L bracket arrangement that would place the cooler on the front of the radiator mounted vertically??? I don't like mine on the bottom either, blew a pin hole in an tranny cooler line once on a coupe and oiled down the right slick at about mid track!!! A very exciting ride but not one I would reccomend to others!!! I put an inline mounted vertically on a '35 for a customer awhile back, so far it's been working great.

Dave is right, inline is a good way to go. That is what I just got put on my 66 when I got my new C4. Which actually my truck is STILL at the shop after 3 weeks now when it was supposed to take only a week. But yeah the guy recommended a inline cooler so that is what I got. I would think it is better since it will be at the radiator and do what Dave said, get more air flow.

If you're going to run a spreader bar, this may work for you.

I've been running the front spreader as a trans cooler since the car was first running in 1993.

An additional help for trans cooling is a Derale trans pan on the T-400. (These have longitudinal tubes through them to help carry heat away and they're about an inch deeper as well.)

Whatever you do, install a trans temperature gauge and monitor trans temps.
Especially if you have a higher than stock stall speed converter.

This trans cooler works well and the only place the trans gets warm is climbing the slow switchbacks into Sequoia Nationa Park.
The higher than stock stall speed converter doesn't lock up solid at slower speeds - in 2nd gear - and adds heat on a hot summer day.

The spreader shown on the 32 is 2" OD, about .063 wall thickness.
Surprisingly no one has ever commented on the larger than normal OD of the spreader bar.

My 31 gets a 1 3/4" spreader bar/trans cooler and the fittings on that one will enter and leave from the top with 90 degree turns to the back.
That bleeds the air out better than the horizontal fittings on the 32 do.

Effective radiation area on the 32's spreader/cooler is in excess of 120 square inches.
The 31 will have a little over 100 square inches of radiation area.

Dark colors radiate heat better.
The 32's spreader/cooler is powdered black and the 31 will end up the same.

A lot of folks notice the braided lines up front, but only a few have figured out what they're for.

A more extensive write-up including an exploded view of the 31's spreader/cooler is in Rod & Custom Mag.
About November 2-3 years ago I believe.

Thanks all, that does give me some ideas since I am getting better at making brackets from angle iron. They are a bit clunky but underneath that's OK. C9 the spreader bar cooler is amazing. I'll bet you could even weld/heliarc a few vertical fins on the bar that would look neat. I assume the tube is aluminum? Let me look around for somebody to heliarc some Al. Trailing edge blades would look neat, but give away the function. It looks like I could still use a front bumper along with the cooler if I use a sturdy mounting bolt. I can see how to sketch/design it but it will depend if I can find somebody at the nearby airport to fabricate it. I guess steel would work but not as well as aluminum. Otherwise it is back to making some brackets to mount a small plate cooler like a radiator across the air flow underneath. lts10, you guys are amazing, of course there are a lot of bolts under there to piggy back on. I should have thought of that. I recall a neat picture of the underside of C9's '32 but he has so much neat stuff packed in under there I did not see how he had a cooler and of course it was in the spreader bar all along! Good to hear from Dave and reassuring that I guessed right about potential damage uinderneath. I guess what several of you are calling "in-line" is the type of cooler that is a tube surrounded by aluminum fins but that type has to be put in a protected place.

Don Shillady
Retired Scientist/teen rodder

I had a cooler mounted underneath my ford thinking that it would have good airlow. What i did not account for is the extreme summer heat heating up the road and having that heat radiating back up from the ground up into the cooler. Found that out a couple of years ago on my back home from a show in corpus christi. About 30 miles from home i started throwing oil out of the breather. After that, I mounted a cooler in front of the radiator. Problem solved.

Might not help you, but IHC used a cooler that hooked in to the heater hoses. It was a cylinder about 10" long and 1.5" diameter that could be mounted anywhere since it was water cooled.

in the automotive repair business, we always put the cooler in front of the radiator...I've also seen other shops put them behind the radiator...

Originally posted by Don Shillady
Thanks all, that does give me some ideas since I am getting better at making brackets from angle iron. They are a bit clunky but underneath that's OK. C9 the spreader bar cooler is amazing. I'll bet you could even weld/heliarc a few vertical fins on the bar that would look neat. I assume the tube is aluminum? Let me look around for somebody to heliarc some Al. Trailing edge blades would look neat, but give away the function. It looks like I could still use a front bumper along with the cooler if I use a sturdy mounting bolt. I can see how to sketch/design it but it will depend if I can find somebody at the nearby airport to fabricate it. I guess steel would work but not as well as aluminum. Otherwise it is back to making some brackets to mount a small plate cooler like a radiator across the air flow underneath. lts10, you guys are amazing, of course there are a lot of bolts under there to piggy back on. I should have thought of that. I recall a neat picture of the underside of C9's '32 but he has so much neat stuff packed in under there I did not see how he had a cooler and of course it was in the spreader bar all along! Good to hear from Dave and reassuring that I guessed right about potential damage uinderneath. I guess what several of you are calling "in-line" is the type of cooler that is a tube surrounded by aluminum fins but that type has to be put in a protected place.

Don Shillady
Retired Scientist/teen rodder

The trans coolers in both cars are steel tubing, about .063 wall.
Aluminum would probably work better, but the powdered black tubes are doing the job.

Keep in mind you're running a very lightweight car and you don't need the trans cooling capabilities of a trailer towing pickup.

My drag racing friends who run automatics run a simple loop of hard tubing out of and back into the trans.
They don't operate long enough to overheat the trans.
Even when they run a trans brake.


The coolers are easy to make, tubing cut to length with square ends.

Chamfered on the inside a touch.

A couple of CR (Cold Rolled) steel plugs machined to a snug sliding fit inside the tubing.
Weld or braze these into place.

Said plugs center drilled and tapped 1/2-13 for the single bolt that retains them. (They bolt to the front spreader bar hole and the back hole is filled. The slight movement of the spreader bar toward the front gives an additional allusion of lowness.)

You'll need to make a half circle of CR 2" wide to match the frame width and the proper thickness to fit the OD of the tubing you're using.
Weld it on with the cooler bolted in place so that the cap fits both frame and tubing cooler.
Finish to bodywork standards.

If preferred, you could use both spreader bar bolts and duplicate a spreader bar adding only the threaded hose bungs.

Threaded hose bungs are easy.
Couple of ways to do it.

Get a couple of steel #6 AN fittings with 1/4-NPT on the other end.
Weld or braze these into a drilled hole in the cooler tubing.

A couple of steel reducers, 1/4-NPT female and whatever works on the other end.
Bigger than 1/8-NPT so as not to cut down on flow.
Weld or braze these into place.

If you go aluminum tubing, be aware that Earls carries aluminum threaded weld-on bungs.

Welding is not necessarily required on these coolers.
You can use JB Weld on the mild steel stuff and epoxy the components into place.
That could limit you to the finish you desire to put on the cooler.
JB Weld is good to about 600 degrees F.
Powder coating runs to about 400 degrees F.
I'm not sure if the 200 degree safety margin is enough.

If you go aluminum, places like MSC and McMaster-Carr carry alloy specific epoxies. (Steel, stainless steel, aluminum, etc.)

You can't see it on the 32, but it has a welded thread bung in the bottom center of the cooler.
I thought a drain plug could be handy, but it's never been used.

The license plate is retained by a pair of threaded weld bungs (1/4-20) with blind holes.

The cooler mounting bolt on the 32 is a 1/2-13 black oxide button head allen bolt.
I'd had good luck using powder coated bolts in other areas and figured powdering the button heads would work well.
It did.
They've been through several on-off cycles with no wear & tear evident on the internal hex.

One thing you can't see on the underside photos of my 32 is that there is room in front of the rear axle, up high close to the body to install an electric fan cooled trans cooler.

So far, it's not been needed.


As a small side not about the color black being the best to radiate heat - I get arguments now and then - black is the correct color to use.
Information obtained from sailplane panel tests as well as observing motorcycle engines in the off-road arena.

For a long while, dirt bikes came with natural aluminum engines.
After a time, they started anodizing the cylinders and heads black to assist engine cooling in MX and desert races.

A friend of mine was adamant that white was the correct color to use and painted his natural aluminum finished Yamaha 250 enduro cylinder and head white.
He was thinking reflectivity and not radiation.

Sure enough, first time out on the Dez, he was trying to keep up with us and seized a piston.
Something that had not happened before when the engine was natural aluminum.

Couple weeks later, new piston, fresh bore, black paint....

Hmm that is weird. Now what if you pc'd (powder coated) a engine block black? Would that help? Sorry if that sounds dumb but just wondering. My Husqvarna 510 dual sport motor is ALL black maybe for that reason. It was used in the colorado 500 race and mexican desert race too.

black is the "perfect" radiator and adsorber of heat. White is the reflector of heat.

For a water-cooled motor, the radiated heat from the block is small compared to the heat dissapated by the air/water radiator.

So, to answer your question, coating the block flat black theoretically helps. But paint can be an insulator too!

Like C9x said, air cooled bike engines need all the help they can get so flat black is the solution for them.

mike in tucson

How about gloss black? The motor on my Husky is flat black but I do plan to paint the block gloss black on the next 302 that goes on the truck and possibly powder coating the block that goes into the 48 one day since I do my own powder coating anyways.