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Site Team
Join Date: Feb 2003
Location: The mountains of Scottsdale, AZ, and the beaches of Maine
Posts: 10,104
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Interim report -
I've just done my first thousand miles with the Interceptor. The trip was from Scottsdale, AZ to Lyons, CO. This is the first leg of our semi-annual migration between Arizona and Maine, so the TM was loaded as heavily as it ever is. The Interceptor was fun, and I learned a couple things.
First, I chose the optional blue-on-blue color scheme of the Interceptor readout, in a black bezel case. I still like the blue-on-blue, but it washes out pretty badly in direct sunlight. From a practical point of view, something with more contrast, like black-on-white, would have been better.
Second, this was not a tough trip from the tow vehicle point of view. The worst part is Raton Pass, at the New Mexico-Colorado border. It tops out at just under 8000 feet. At that point, altitude is becoming a consideration for my Explorer, but not yet a handicap. And the grades didn't exceed about 6-7%, although there were several miles of such grades.
My Explorer has a 5-speed automatic transmission. On the flats, I leave overdrive enabled, which cuts the engine RPM, of course, and presumably increases gas mileage. My first surprise was that in 5th gear, the transmission temp runs about 185, whereas if I pull it down into 4th, the temp drops to about 170. Both very reasonable temperatures, but I don't know why it is higher in 5th than in 4th. I am quite sure that the torque converter locks up in both cases. So for now it remains a mystery.
The second surprise is that downshifting for engine braking on a downgrade raises the transmission temp quite a bit. I saw my only instance of 190 degrees during a long downgrade when I had pulled it down into third gear /50 mph. Again I'm not sure why, because I think (this time I am not sure) that the torque converter locks up in this condition, too. But even if I don't downshift, the transmission runs hotter going downhill than it does going up an equivalent grade.
Finally, on the steepest upgrade, I downshifted to third and manually held the engine RPM to 4000 or less. This allowed me to maintain 50 mph without straining anything. And during this time, the transmission was loafing, temperature-wise, seeming to run at about 165 no matter how long I did this. The engine coolant temperature, by contrast, max'ed out at about 214 during this climb. That was the highest I ever saw for this parameter - it normally runs rock solid at 200, which I presume is the thermostat setting.
So all in all it was fun, and I have stopped being quite so paranoid about transmission temperature in my particular vehicle. Other vehicles may react differently, of course.
If I learn anything more of general interest, I'll report it. By the way, I don't think I ever pointed out how easy this thing was to install. Step 1 - plug one end of the supplied cable into the back of the Interceptor. Step 2 - plug the other end of the cable into the OBD-II connection under the dash, right beside the steering column. Step 3 - have a beer in celebration of a job well done.
By the way - no tire failures! Wahoo!
Bill
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