Thread: Over Drive
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Old 09-16-2009, 06:48 AM   #11
mtnguy
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I am pulling a heavier trailer now, but some of this info might be helpful here.

I always thought my 1st downshift from OD (4th) was back to 3rd.......NOT!!! After buying a ScanGauge II and setting it up to monitor gear ratio and torque converter slippage, my 1st "downshift" is actually my torque converter unlocking. If I use the button to lock out OD, then both the tranny goes to 3rd, and the torque converter unlocks, but if the engine is not under a heavy load, then the torque converter locks right back up. Pulling my full sized trailer on the interstate, and manually shifting the OD off and on as needed in the hill country around here, the tranny temp. stays in the 155 to 170 degree range. The pull up the winding mountain roads around here in 2nd gear, torque converter unlocked will send the tranny tempurature to 200 degress on a hot day. The problem there is that I have to slow down for the curves, so the speed has to stay down...hence 2nd gear and torque converter slipping. On more straight line Interstate over the mountains where I can keep my momentum, then 3rd gear with the torque converter locked is the norm......keeping up with traffic is no problem.

I do intend to replace the tranny fluid every 30,000 miles or so.
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