Lets see if any techs have an idea, hell it might even be normal........2001 f-350, have about 2000 miles on an ATS tranny,heres whats going on, I hooked up a TC lockup switch with green led to tell me when the comp is locking up TC. Never used the switch cause stock tranny always stayed locked in coasting and with brakes on above 40, anyways I put in the ATS, never use the switch cause TC acts just like stock one did, I left the switch and light in though just to have the light and know when my TC is locking up just cause I like to know. Anyways shifts are great everything feels fine, except the last few days, ( it has been in the single digits down to -10in the morning) I let the engine come up to temp, pull on to the highway, I take it easy, no hard accelerating, no hills, its level with a little down if anything, but tranny hasn't been locking torque converter or going into OD even at 70 until 2-3 miles down the road, then it shifts fine. At night coming home, wich hasn't been alot warmer than morning, 1st, 2nd, 3rd, TC lockup,OD just like it should. Have Mobil full synthetic in it, any ideas???