The usual cause for the symptom is hardened internal rubber lip seals on servos or clutch drum pistons. With the transmission is cold, the lip seals stick in their “at rest” positions. When fluid pressure is first applied, they will not move for awhile, but when they finally do they will function until the transmission cools down and the process is repeated. Additives that are formulated to soften internal seals will usually do more harm than good for the transmission in the long run. There is no way to control the affect that additives have on the seals, and therefore, the repair of the problem is to overhaul the transmission. The degree of “hardness” of the various seals in a transmission will vary greatly. The seals that are not hard will be softened to a gummy, swollen mush.
When the transmission reaches operating temperature, the seals are softened enough to function properly. Invariably, this problem will get worse with age and colder temperatures.
