Prefered Transmission coolers

[shanneba]

My 2003 BMW 330Ci has an auto trans with a fluid cooler at the bottom of the radiator. It also has a coolant temp sensor in the bottom radiator hose. My OBDII software allows recording data, here is an hour drive from April of this year. Outside temp was about 72. Data is trimmed down to every minute, the recorded data has about 700 datapoints per minute.
Code:




Time Engine Vehicle Coolant Coolant Ignition Injection Oil Temp

Speed Speed Engine Outlet Timing Duration



07:24:31.625 0 0 91 86 7.7 0 92

07:25:00.343 930 0 94 86 -11.1 7.28 92

07:26:00.015 797 5 120 86 -2.1 4.27 95

07:27:00.031 729 0 144 86 3 4.51 105

07:28:00.000 2345 58 164 86 24.8 8.26 119

07:29:00.000 2180 58 184 86 28.4 4.98 138

07:30:00.015 1784 51 191 87 28.7 1.9 155

07:31:00.109 1830 50 194 90 26.8 4.24 166

07:32:00.046 1897 51 195 101 28.7 3.72 175

07:33:00.343 2178 42 194 109 22.5 8.06 179

07:34:00.171 1720 47 195 117 27.6 2.76 188

07:35:00.000 1738 47 198 118 26.8 3.94 192

07:36:00.031 1697 47 198 118 26.4 3.78 196

07:37:00.031 1737 47 196 124 26.8 3.77 201

07:38:00.000 1629 41 198 122 22.1 6.14 204

07:39:00.312 1905 53 196 129 28.7 3.8 205

07:40:00.281 1910 52 198 125 25.6 5.04 206

07:41:00.437 2745 59 190 175 7.3 10.97 209

07:41:00.484 2745 59 190 175 7.3 10.97 209

07:42:00.421 2309 65 183 157 26.8 6.76 211

07:43:00.000 1923 52 195 124 29.1 3.8 211

07:44:00.015 1922 50 196 126 28.4 4.06 211

07:45:00.000 1245 39 198 126 -12.7 1.57 212

07:46:00.015 1850 52 198 136 25.6 4.73 212

07:47:00.125 2006 55 194 137 29.5 4.01 214

07:48:00.359 1869 55 196 130 28 1.47 214

07:49:00.406 1640 39 195 124 22.5 5.29 214

07:50:00.015 1496 30 195 156 25.2 2.66 212

07:51:00.000 755 0 199 149 13.9 3.96 211

07:52:00.000 1778 48 194 152 28 2.82 216

07:53:00.000 2117 58 186 168 29.9 3.9 216

07:54:00.000 2094 58 195 124 28.4 4.76 214

07:55:00.328 2270 65 188 156 29.5 4.3 216

07:56:00.375 2029 55 195 128 27.6 4.58 216

07:57:00.000 2285 63 196 137 29.1 4.61 216

07:58:00.031 2312 64 195 138 29.5 4.21 216

07:59:00.015 2326 64 195 144 28 5.77 218

08:00:00.359 2426 69 195 140 17.4 11.03 218

08:01:00.343 2515 71 183 164 28.7 5.74 218

08:02:00.281 2236 67 191 136 -4.5 1 216

08:03:00.015 966 24 196 117 2.6 2.13 212

08:04:00.203 696 0 202 125 5.7 3.51 211

08:05:00.125 2593 74 183 180 31.9 4 218

08:06:00.296 2593 74 192 136 29.5 5.14 216

08:07:00.015 2539 72 198 134 29.5 4.54 218

08:08:00.156 2549 72 196 134 29.5 4.74 218

08:09:00.203 2534 72 196 133 31.9 1.84 218

08:10:00.140 2524 72 196 134 29.5 4.61 219

08:11:00.312 2548 73 196 133 29.5 4.81 218

08:12:00.015 2454 71 198 138 31.5 1.68 219

08:13:00.031 2445 70 198 138 22.1 7.1 219

08:14:00.000 2465 71 198 137 32.7 2.45 219

08:15:00.437 1673 44 195 128 26.8 3.55 218

08:16:00.015 2483 71 183 182 -2.1 1 218

08:17:00.359 705 0 182 157 4.5 3.53 214

08:18:00.031 701 0 200 138 4.1 3.62 212

08:19:00.296 703 0 203 151 4.5 3.62 212

08:20:00.343 2542 72 191 190 29.9 4.51 218

08:21:00.000 2464 70 184 164 26.4 5.99 218

08:22:00.078 2121 58 195 125 28.4 4.53 216

08:23:00.359 2132 59 198 133 29.9 4.06 216

08:24:00.218 2137 59 198 140 28.7 4.23 218

08:25:00.015 2541 73 186 173 21.7 6.32 218

08:26:00.015 2544 73 195 136 28.4 5.38 218

08:27:00.031 2554 73 196 136 26 6.16 219

08:28:00.093 2546 73 198 141 29.1 4.68 219

08:29:00.437 2517 71 196 138 29.5 4.54 219

08:30:00.015 2532 72 198 140 30.3 4.34 222

08:31:00.265 2194 63 198 136 28 5.02 219

08:32:00.000 702 0 202 141 4.1 3.61 216

08:33:00.015 1975 17 202 173 24.8 4.35 218

08:34:00.203 721 0 204 169 3.7 2.6 218

08:34:20.687 698 0 204 167 5.3 2.62 218

The car has a ECU controlled thermostat, when the engine coolant temp drops to the mid 180s above, it is after I hit over 3000 rpm. The ECU seems to cool the engine down to about 180 when the load / engine speed increases. It runs about 200 with the cruise set, low load conditions.

 

[unDummy]

More gears = less time in TC unlock = cooler transmission
Less gears mean more time with TC slippage making up for being in the wrong gear all the time = hotter fluid.

Narrower ATF temp range leads to more efficient programming for MPG, longevity, and shift quality. But, they play the game of statistics, warranty and manufacturing costs. What if you exceed the capability? for an excessive amount of time?

 

[lobo11]

Man I am not sure if an added auxillary is needed if the built in tranny cooler in the radiator is anything like the radiator. The return line from the radiator has got to be the coolest returned fluid I have ever had from any vehicle I have ever owned. The fluid going to the radiator, hot as can be, hose hot to the touch, but the return out of the radiator is positively cool, maybe not cool but the coolest I have ever experienced. Not sure how that could translate to the transmission cooler, but impressive to me none the less.