TH350 Transmission Oil Capacity
The Short Answer
The TH350, also called the Turbo 350, takes a very different amount of fluid depending on the job. A routine pan drop and filter change is commonly listed at about 2.5 to 3 quarts. A completely dry transmission with an empty torque converter, such as after a rebuild, is commonly listed at about 10 quarts. These are widely published approximations, not figures checked against a specific factory service manual for this article. Use them as a starting point, then set the final level with the dipstick.
Service situation | Commonly cited approximate fill | Notes; Pan drop and filter change (stock pan) | About 2.5 to 3 quarts (about 2.4 to 2.8 liters) | Most fluid stays in the torque converter and cooler lines; Dry fill after rebuild, including converter | About 10 quarts (about 9.5 liters) | Varies with converter size, pan depth and cooler setup
Why the Number Varies
The TH350 was fitted to many General Motors cars and trucks across a long production span, and it is also common in aftermarket and swap builds. Several factors change how much fluid a given unit holds:
Torque converter: Converter diameter and design affect how much fluid it holds. Aftermarket stall converters may hold a different amount than the original unit. Pan depth: Deep or extra-capacity aftermarket pans hold more fluid than the stock pan, which raises both the refill and total figures. Coolers and lines: Auxiliary coolers and longer lines add capacity beyond the factory setup. Drain method: A pan drop removes only part of the fluid. Draining the converter or flushing the cooler lines removes more and requires more to refill.
Because these factors differ from one vehicle to the next, no single capacity number fits every TH350. If you need an exact figure for a specific model year and vehicle, check the factory service manual for that application. This article does not include one.
Setting the Correct Level
The dipstick reading at operating temperature is the real target. A practical approach is to add somewhat less than the expected amount, start the engine and move the selector through each gear. Return to Park, then check the dipstick with the engine running and the vehicle on level ground. Top up in small amounts, rechecking each time, until the level is within the marked range once the fluid is fully warm. Both overfilling and underfilling can cause problems, so add fluid gradually rather than pouring in a fixed quantity.
The TH350 uses a Dexron-type automatic transmission fluid. Confirm which current fluid specification suits your unit, especially if it has been rebuilt with aftermarket parts, because this article does not cover fluid compatibility in detail.