TrailManor Owner's Forum - View Single Post

01-17-2010, 08:56 AM

To add a little to Bill's post #10.

I use a Scan Gauge II to monitor my transmission temperture. In addition, I monitor my torque converter slippage and gear ratios. I have learned a lot by watching that little puppy. I used to think that the 1st downshift that occured from 4th gear was the transmission going back into 3rd. But the 1st downshift that I feel on my 2006 F150 is the torque converter unlocking, while the transmission stays in 4th. It will then switch down to 3rd if additional power is needed. When I manually disable the O/D, then the transmission shifts to 3rd and the torque converter unlocks, but the torque converter will immediately lock back up if addtional power is not needed. As far as I can tell in my vehicle, the torque converter never locks up in 1st gear.

Climbing the steep curvy roads around here pulling my conventional 5500 lb. travel trailer, the transmission will shift to 2nd gear, with the torque converter unlocked. With the unlocked torque converter, and low speeds, that is when the tranny temperature really goes up. I have gotten 200 degrees before I crest the top at Swfit Run Gap. Crossing the Blue Ridge at Afton mountain on I-64 where I can keep my speed up (no slow-down curves), with the tranny in 3rd and the torque converter locked, the tranny temperature stays below 180, and usually below 170.

I am now a believer that an unlocked torque converter is the main culprit of transmission temperature heat.

01-17-2010, 08:56 AM	#13
mtnguy Guest Posts: n/a	To add a little to Bill's post #10. I use a Scan Gauge II to monitor my transmission temperture. In addition, I monitor my torque converter slippage and gear ratios. I have learned a lot by watching that little puppy. I used to think that the 1st downshift that occured from 4th gear was the transmission going back into 3rd. But the 1st downshift that I feel on my 2006 F150 is the torque converter unlocking, while the transmission stays in 4th. It will then switch down to 3rd if additional power is needed. When I manually disable the O/D, then the transmission shifts to 3rd and the torque converter unlocks, but the torque converter will immediately lock back up if addtional power is not needed. As far as I can tell in my vehicle, the torque converter never locks up in 1st gear. Climbing the steep curvy roads around here pulling my conventional 5500 lb. travel trailer, the transmission will shift to 2nd gear, with the torque converter unlocked. With the unlocked torque converter, and low speeds, that is when the tranny temperature really goes up. I have gotten 200 degrees before I crest the top at Swfit Run Gap. Crossing the Blue Ridge at Afton mountain on I-64 where I can keep my speed up (no slow-down curves), with the tranny in 3rd and the torque converter locked, the tranny temperature stays below 180, and usually below 170. I am now a believer that an unlocked torque converter is the main culprit of transmission temperature heat.