Hello. In my '88 240DL Auto I have been low on tranny fluid by about 5 to 6 ounzes every 100 miles or so. I checked everywhere and can not see a leak. I changed,flushed fluid. Changed tranny filter. Someone suggested changing radiator as may be leak there and tranny fluid is going into coolant. Could this be ? Any suggestions of where to check or what to try next ? Note that I check with car cold. then I let car idle for 10 minutes. Go thru all gears. Let idle another 2 minutes and then I pull out dipstick, wipe it clean, then restick it in, and then check. It has been cold here in NJ. Should I let car idle maybe 15X minutes instead of 10 ?