If the transmission delays initial gear engagement after being parked overnight or longer, it may be due to a suspect transmission cooler return filter. If the transmission was recently serviced and the part number for the cooler return filter contains an "AB" suffix at the end, a new filter should be installed.
Replace Transmission Cooler Return Filter if it Has "AB" Suffix on Dodge Ram 3500
Average mileage: 125,000 (125,000–125,000)
Drive Trains affected: 2WD, 4WD
6 people reported this problem
After sitting overnight transmission slow to shift into drive, if I shift to reverse and then back to drive it works okay.
2001 Dodge Ram 3500 - 4WD
Transmission will not engauge if left over night till warmed up then will run fine.