Well im starting to wish i had never bought my zj. Bought my 5.9 zj with a blown rear diff and transmission, replaced both and drove well for about a year now. For the last two weeks i have been prepping it to sell, repairing all the little things and cleaning it up. Anyway for the last week when i go to leave in the morning i throw it in reverse and its all good, back up a few feet and shift in to drive... nothing no movement for about 1-2 seconds. After those few seconds it grabs and takes off driving and shifting fine all the way to work. Work 8 hours and go to leave, no need to reverse where i park, straight into drive, takes off great. I talked to a transmission shop and he said it could be a bad torque converter drain back valve and to put it neutral before leaving to fill it up. But it seems to be fine in reverse and wouldnt that time in reverse be enough to refill the tc? Another thing i noticed is that the colder it is the worse the problem is this morning was -7c and when i put it in reverse i did that slip and then i put it neutral for a couple seconds before drive and i got a slip. I then drove it maybe 50 feet and shifted between reverse and drive a few times and it was fine. I dont feel comfortable selling it the way it is but i need it gone. any help?