When the vehicle sits over night, fluid from the torque converter drains back into the pan area. When the vehicle is started, it takes a few seconds for the fluid to refill the converter. This “refilling” process will not fully occur until the unit is placed into any other gear position than park. This is a normal idiosyncrasy of a torque flight transmission.
Also, if the engine/transmission mounts are bad and the engine rpm is above idle, there will be a noticeable “thump” when the reverse engagement occurs.
If this symptom occurs after the vehicle is driven, there are other problems with reverse.
Note: There is a valve body kit that will eliminate this symptom in the rear wheel drive versions only.
