not upshifting

[balistic]

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???

[balistic]

any ideas, it's still doing it in the morning only, even though it has warmed up a bit here??

[Nosparkplugs]

Sounds pretty normal the truck tries to let the trans warm up before it shifts

[NCHornet]

I agree it sounds normal, fluid has to be warmed up before she is going to shift normal. I wouldn't worry about it. Spring is on the way!!!

[balistic]

but why doesn't it do it going home. the truck sets longer at work than it does at home, and it is warmer now in the morning (LO 30'S)than it was two weeks ago in the afternoon(LO 20'S). A temp deal isn't making since to me