Overheating is one of the most common reasons people give when asked why they don’t drive their project cars. Even if a car isn’t running in the danger zone, bringing operating temperatures closer to the low end of normal can preserve component life, extend fluid life, and relax nervous gauge-watchers.
One oft-overlooked way of lowering engine temperature is to improve the automatic-transmission cooling. Think about it: The engine and trans are locked together, and unless you’ve added an external trans cooler, your red fluid is running through your radiator, bringing additional heat to your engine coolant. Aftermarket companies have claimed that an extra-capacity aluminum pan with heat-sink fins will help cool off the transmission. But is it true? We decided to use our 1969 Dodge Polara as a test mule to find out.
The TCI pan we used holds an extra 2 quarts and hangs down about 2 inches below the stock one. We haven’t had any ground-clearance problems.
The car runs a 440 with a 727 TorqueFlite and a 2,500-rpm-stall, 11-inch converter. We’ve never had any problems with overheating, but we never checked the trans temperature before, either. The first step was to get a baseline with the stock pan. Auto Meter sent us one of its full-sweep, Sport Comp II electric trans-temp gauges (PN 3658, $176.33 at SummitRacing.com) and we went for a drive. After 20 minutes of regular driving (some freeway, mild traffic, a moderate hill) our trans temp was at 200 degrees F.
Next, we installed a deep, finned pan from TCI (PN 128000, $154.95 at SummitRacing.com). The installation was so quick it’s barely worth mentioning, though an adapter to lower the filter for the deeper pan needs to be installed; a speed wrench and a drain pan, and we were ready for our next test. We took the exact same route, and conditions were as similar as possible. We pulled back in to the driveway having seen a max trans temp of 190 degrees. ATF life is shortened by half if the transmission is run at temperatures exceeding 200 degrees, so even reducing the temperature by 10 degrees can make a difference. The ease of this swap makes it well worth doing, especially for those of you planning on racing or towing.
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