How do you tell the difference between a trimatic and turbo bolt pattern?

The Trimatic and Turbo Hydra-Matic transmissions used in GM vehicles from the 1960s to the 1980s have different bolt patterns. The Trimatic has a six-bolt bellhousing pattern, while the Turbo Hydra-Matic has an eight-bolt bellhousing pattern.

To tell the difference between the two transmissions, you can look at the number of bolts holding the bellhousing to the engine block. If there are six bolts, it is a Trimatic. If there are eight bolts, it is a Turbo Hydra-Matic.

You can also measure the diameter of the bolt pattern. The Trimatic's bolt pattern is approximately 10 inches in diameter, while the Turbo Hydra-Matic's bolt pattern is approximately 11 inches in diameter.

Here is a table summarizing the differences between the Trimatic and Turbo Hydra-Matic bolt patterns:

| Transmission | Number of Bolts | Bolt Pattern Diameter |

|---|---|---|

| Trimatic | 6 | 10 inches |

| Turbo Hydra-Matic | 8 | 11 inches |

By following these steps, you can easily tell the difference between a Trimatic and Turbo Hydra-Matic transmission.