Hi, I recently purchased a '99 Durango (5.2l 4X4) that needed a transmission. The new trans works just fine except for the torque converter unlocking. It has normal shifts and lockup in overdrive but doesn't unlock until you press the accelerator enough for it to down shift. Then it unlocks, down shifts, then back up and locks again. Tapping the brake will cause it to unlock. The speed sensor is new. I've checked the TPS and it is good. The TV cable is also adjusted correctly. I have an '01 Durango and an '11 Dakota and both of them will unlock the converter on OD without down shifting also. I haven't been able to find much information on this concern and don't know if it's a problem or not or is normal. Any help would be greatly appreciated.

 

Is it unlocking when you slow down to below 40-45mph? If so that sounds completely normal to me.

 

The 44re and 46re lock in O/D above a certain speed, usually around 35-45mph depending on the axel ratio. They don't do like most and unlock when you put your foot down til it goes to downshift.

 

Yes it does lock up between 45-50. I'm fine with this being normal I just didn't know mainly due to my other vehicles behavior but I also know that they are fully computer controlled. Thanks a lot for the info.

 

I'm pretty sure it's more efficient this way too.

 

It should be, eliminating the slip in the TC sends direct power to the transmission at the speed and toque it leaves the engine. So you do get better efficiency when its locked up than when its not.

 

Well the 44/46re are not completely computer controlled. You can unplug the main harness for the trans and manually shift the first 3 gears. You lose lockup and O/D when its unplugged. It is basically the old 727 torqueflite 3spd with some electronics and an O/D unit bolted to the rear. Its kind of interesting.

 

Great statement.

It still could be the TPS if you think your having issues. Not an expensive part ya know.