We all have transmissions in our cars, like it or lump it. Automatic transmissions exist in a great percentage of today's cars, and they have become excellent performers for racing applications over the years. Yet, very few of us know how they work, and most don't care as long as they work. Out of the dozen or so vehicles I have owned over the years, only one ever had an automatic tranny in it. In some of the hot rod shops I've worked, I installed tranny coolers in cars that were being built, but only because they were supposed to coincide with the automatic. I wasn't sure how to figure out what kind or size was necessary for the application. I was simply reassured that "this one" will work well, according to the salesman.
As it turns out, it's not that hard to find out what you need. Rather, it is critical you have one in the first place and that it cools enough for your application. I contacted a few reputable companies and picked their brains to come up with some basics everyone should know.
Automatic transmissions generate large amounts of heat, and are totally dependant on the transmission fluid for cooling. When the fluid temperature exceeds 200 degrees F, the fluid deteriorates rapidly, diminishing its ability to lubricate and cool critical valves, springs, seals, and other internal components, leading to premature failure and costly repairs. Over 90 percent of all automatic transmission overheating causes failures.
A 20-degree drop in fluid temperature can double the life of the transmission. This unanimous statement came from both Perma-Cool (909/390-1550, www.perma-cool.com), a top manufacturer of tranny coolers, and Hughes Performance, known for its automatics of brute strength. The stock cooler is marginal for any performance applications or towing duties. The inefficient factory fluid cooler is located in the radiator's coolant holding tank where hot tranny fluid is cooled by transferring its heat to the colder engine coolant that surrounds it. The minimal temperature difference between the two fluids under normal conditions causes little, if any, drop in the transmission fluid temperature.
You can now see the necessity of a tranny cooler. Generally, a good starting point is to get a low restriction four-pass cooler with 1/2-inch or 5/8-inch tubing. The pass amount refers to how many times the tubing goes through the radiator-type fins. Air flow and low restriction are key in getting those temps down, so plan the routing of the cooler lines as straight and direct as possible while placing the cooler where it will get a good amount of air, like in front of the radiator. Sharp 90-degree bends slow down the fluid flow and impair cooling; try to also use quality fittings and lines. A/N fittings with braided lines would be the most reliable, as opposed to rubber hose with hose clamps on brass fittings. You can try fittings from Earl's (www.raceplumbing.com) or Russell (310/320-1187, www.russellperformance.com).
All you have to do now when ordering your tranny cooler is to give the info on your car and drivetrain combo. There is a plethora of shapes and sizes of coolers to suit your needs, as well as remote mount units that have an electric fan to help your tranny keep its cool.
For most of the country, the winter season has arrived and there isn't much cruising going on. Now is a perfect time to refine some of the areas on your car that might have been overlooked during the initial build, such as hardware. All of our cars are put together with a variety of nuts and bolts. Head types, thread pitches, shoulders, material, and grades are some of the basic variables in hardware selection. Hardware is fairly inexpensive, easy to upgrade, and, in many cases, will make your car safer and look better, as well. Companies like Totally Stainless (800/767-4781, www.totallystainless.com) and ARP (800/826-3045, www.arp-bolts.com) offer specialty hardware to upgrade your car to that next level.
Totally Stainless can supply you with one stainless 3/8-inch 24 bolt or kits for your body, chassis, or motor with many options along the way, such as black stainless, which is a black powdercoating with Teflon that doesn't require anti-seize. It also offers stainless versions of GM-only hardware, such as washers and under-sized interior screws, stainless U-bolts, grease zerks, cotter pins, and even muffler clamps. ARP's Chris Raschke brought power-adders to our attention. You may consider adding some ponies to your motor over the winter by adding a blower, turbo, or nitrous. With all that comes extra stress on the internals of your engine, including the rod and head bolts. Or maybe you have a late-model crate motor and had trouble with the easily rounded flywheel bolts. These are just a few of the critical areas that could use stronger hardware.
If it's happened to you, it's an experience that'll fill your shorts in a hurry. Those rubber brakes lines can present a problem, especially if they have not been replaced for quite some time. Under normal conditions, rubber brake lines are not a problem to about 70 percent of us out there. Here's where they can present a problem: if they are decades old, the rubber could be old and brittle. You must replace them ASAP.
If you fancy yourself a road racer, then you are familiar with hard-stopping conditions. These conditions can flex those hoses, as if they were balloons, and when those balloons deflate, they can send brake fluid in both directions-to the calipers and back to the master cylinder. Any brake specialist can custom-make a set or you can take a stroll through the ads in the back of this magazine. Why take a chance with stopping? When looking for braided lines, try one of the many brake suppliers in SC, or contact a local brake specialty shop in your area to have them fab up some lines for you.