Took off yesterday with cold truck. Got on the highway(2 blocks away) and it would not lock in 5th gear. Eng temp got to 175 and stil no lock. Stop at the next exit and all was fine. I did here a small noise frome the trans that was unusual. The whole time I never used much over 1/4 throttle . It felt like it was kind of searching for gears. I will test it again today when I get home. Could it be just a fluke? Allison just having pms?:confused:

How cold was it outside?

40's

The trans wont let the converter lock up untill a certian temp, what was the temp of the trans or had the needle moved yet?

The Allison will shift different when cold. It will delay the shifts to assist in building heat in the motor and trans. I believe I have read on here that it will not let the convertor lock up until the trans fluid temp is 75 degrees. dosen't sound like you have any problem but your right to be a little easy on it until the temps come up. my2c

It just felt weird. Never acted this way and has been much colder before