Many harsh shifts come from tiny air bubbles, not thick oil. This micro-foaming (tiny bubbles) reduces clutch grip and confuses adaptive control logic. Cold starts increase aeration if the level is even slightly off. Moisture traces can also kill anti-foam additives and raise shift flare. Check after service by idling, then slowly cycling through every gear range. Hold each position briefly, and listen or feel for delayed take-up. Avoid solvent flushes that strip friction films on plates and drums. Pick a fluid that matches the friction profile your unit expects. For a suitable option, see Multi Vehicle ATF (TYPE T-IV).