Most cold-start transmission problems are a result of the internal seals hardening and shrinking, when first running the operating pressures will be low due to fluid leaking by these seals, different transmissions show different symptoms (slipping is common).

Once the transmission warms up, the seals grow and soften sealing the leaks, and the operating pressure returns to adequate levels.

If this is your problem, it is sometimes (temporarily) resolved by pouring a solvent into the transmission to soften seals, sold under many names EX: Trans-X.

I'm not recommending it, but if the transmission is failing, this could help nurse it along until a replacement is found.

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Gone to the dark side

- Jeff